Fermentation, Volume 10, Issue 5 (May 2024) – 36 articles

Porphyridium aerugineum is a unicellular freshwater red microalga that synthesizes and secretes into the culture medium an extracellular polysaccharide (EPS). In this study, algal growth and polysaccharide production, as well as the antioxidant capacity and antitumor effect of Porphyridium aerugineum EPS (PaEPS), were investigated. Cultivation of the microalgae was carried out in a photobioreactor under controlled conditions. Algal growth and the amount of EPS were monitored daily. The accumulated polysaccharide was extracted and lyophilized. At the end of cultivation, the concentration of microalgal biomass and PaEPS reached 3.3 and 1.2 g L⁻¹, respectively. To examine the antioxidant capacity of PaEPS, FRAP and ABTS assays were performed. The cytotoxic activity of PaEPS was evaluated on the tumor cell lines MCF-7 (breast cancer) and HeLa (cervical adenocarcinoma) and on BJ (a non-tumor human skin fibroblast cell line), using MTT assay. The results obtained indicated that P. aerugineum polysaccharide exhibited a high ABTS radical-scavenging activity reaching up to 55%. The cytotoxic effect was best expressed in MCF-7 cells treated for 72 h with 1000 µg/mL PaEPS, where tumor cell proliferation was inhibited by more than 70%. Importantly, the PaEPS treatments did not significantly affect the viability of BJ cells. These findings promote the biotechnological production of P. aerugineum extracellular polysaccharide and reveal its potential as an anticancer and antioxidant agent for future applications. Full article

The global increase in population has placed significant pressure on food security, leading to the emergence of aquaculture as a vital source of aquatic foods. However, rising costs and limited fish meal availability in aquafeeds have driven the search for alternative protein sources. While plant-based ingredients have been integrated into commercial aquafeeds, they come with challenges such as low protein content, palatability issues, and the presence of antinutritional factors. In this context, fish silage, made from fish waste and discarded fish, stands out as a promising alternative technology due to its cost-effectiveness and sustainability attributes. The production of fish silage involves the addition of organic/inorganic acids or lactic acid bacteria to homogenized fish waste, yielding a valuable mixture rich in peptides and free amino acids, offering significant nutritional benefits for animal diets. This review aims to promote sustainable practices in the aquaculture industry by analyzing research results related to ensiling technology, appraising the advantages and disadvantages of using fish silage as a feed ingredient, and focusing on emerging trends in this field. Full article

Biosurfactants are much-discussed alternatives to petro- and oleochemical surfactants. Alcanivorax borkumensis, a marine, Gram-negative γ-proteobacterium, produces a glycine-glucolipid biosurfactant from hydrocarbons, pyruvate, and acetate as carbon sources. Sustainable acetate production from lignocellulose or syngas adds to its relevance for the bioeconomy. This study investigated nitrogen sources and carbon-to-nitrogen ratios (C/N) to optimize fed-batch fermentation for biosurfactant production using A. borkumensis with acetate as the carbon source. Urea enabled high biosurfactant production, which was confirmed in DO-based fed-batch fermentation. Varying C/N ratios led to increased glycine-glucolipid production and decreased biomass production, with improvement plateauing at a C/N ratio of 26.7 Cmol Nmol⁻¹. pH-stat fed-batch fermentation using glacial acetic acid as the carbon source and a pH-adjusting agent doubled the biosurfactant production. Finally, bubble-free membrane aeration was used to prevent extensive foam formation observed during conventional bubble aeration. The efficient production made it possible to investigate the bioactivity of glycine-glucolipid in combination with antibiotics against various microorganisms. Our findings allow for the leverage of glycine-glucolipid biosurfactant production using acetate as a carbon source. Full article

Jatropha seed cake (JSC) derived from Jatropha curcas seeds is a by-product of biodiesel production and, due to its high protein content, has been considered as a potential animal feed ingredient. However, the presence of toxic compounds such as phorbol esters and other anti-nutritional factors limits its use in animal feeding. Several detoxification approaches have been used to tackle these constraints and this review aims to summarize the recent advances in JSC treatment aiming to enhance its potential as an animal feedstuff. The review first provides an overview of the structure and composition of phorbol esters and other anti-nutritional compounds, discussing its toxic effects on different animal species. It then explores several detoxification methodologies giving special emphasis to its effects on the nutritional composition of JSC and on the use of the treated substrate as a feed ingredient in fish, poultry, pigs, and ruminants, highlighting their growth performance, nutrient utilization, and animal health issues. Overall, the review concludes that these treatments hold great potential for the detoxification and utilization of JSC as an animal feed ingredient. However, further research is needed to optimize the treatment conditions, evaluate the economic feasibility, and assess the long-term effects of treated JSC on animal health and product quality. Full article

This work aimed to improve the oxygen transfer mass coefficient (k_La) in mixing reactors, first evaluating the effect of agitation and aeration and then evaluating the influence of the size and concentration of silica microparticles. Silicon dioxide synthesized via the sol-gel technique, commercial sand, and beach sand were characterized by particle size distribution, scanning electron microscopy, XRD, EDS, FTIR, TG/DTA, and BET. The particles presented average values of approximately 9.2, 76.9, 165.1, and 364.4 µm, with irregular surfaces and different roughness. Silica sol-gel is amorphous while beach and commercial sand have a crystalline structure consisting of silicon, oxygen, and carbon residues. Silica sol-gel presents a higher loss of mass and surface area than other silica microparticles, with a shallow mass loss and a smaller surface. Increasing aeration and agitation improves the k_La, as well as adding silica microparticles. The best k_La was found using silica microparticles with approximately 75 µm concentrations of 1.0 g L⁻¹ (silica sol-gel) and 2.0 g L⁻¹ (commercial and treated beach sand). All silica microparticles used in this work improve mass transfer performance in mixing bioreactors. Full article

The aim of the experiment was to investigate the effect of different ratios of excipient (millet hull or wheat bran) and LAB inoculation on the fermentation quality and in vitro digestibility of a mixed silage of SCPBs. The preliminary experimental results showed that inoculating with lactic acid bacteria (LAB) directly in the fresh sweet corn processing byproduct (SCPBs) silage had a higher ammonia nitrogen/total nitrogen (AN/TN) ratio and lower silage fermentation quality due to high moisture content. Subsequently, millet hull or wheat bran were mixed with SCPBs in a 7:3 (T₁), 8:2 (T₂), and 9:1 (T₃) ratio and ensiled with LAB. Under the condition of each mixing ratio, the silage treatments were categorized into groups without any additives (control) and with LAB. Fermentation quality, in vitro digestibility, chemical composition, and energy values were determined after 45 days of silage. The pH, AN/TN, neutral detergent fiber, acid detergent fiber, and acid detergent lignin were lowest in the SCPBs and millet hull mixed silage (SMH) group under the T₃ treatment, whereas they were lowest in the SCPBs and wheat bran mixed silage (SWB) group under the T₂ treatment. The mean lactic acid and acetic acid values were higher in the SWB group than in the SMH group (6.92, 6.81 vs. 4.00, 4.52). Under the T₃ treatment in the SMH group, AN/TN was significantly reduced with the addition of LAB (4.52 vs. 4.37, p < 0.05). The SMH group had the highest crude protein (CP) under the T₃ treatment, whereas the SWB group had the highest CP under the T₂ treatment. The mean CP in the SWB group was higher than that of the SMH group (18.17, 19.44 vs. 10.55, 10.55). Under the T₁ treatment, in the SWB group, the addition of LAB resulted in a significant increase in in vitro crude protein digestibility (p < 0.05). The results showed that silage fermentation quality and in vitro digestibility improved with the addition of LAB. The optimum mixing ratio for the SWB group was 9:1 and 8:2 for the SMH group. Full article

There is a trend towards the commercialisation of strawberry tree fruit spirit (AUS) with wood ageing, motivated by its favourable sensory characteristics. Additionally, further studies are necessary to elucidate the optimal conditions regarding ageing time and toasting level. This study evaluated the changes in colour and low molecular weight compounds (LMWC) of AUS aged for three and six months using oak wood (Quercus robur L.) with light, medium and medium plus toasting levels. For this purpose, phenolic acids (gallic, ellagic, ferulic and syringic acids), phenolic aldehydes (vanillin, syringaldehyde, coniferaldehyde and sinapaldehyde) and furanic aldehydes (furfural, 5-hydroxymethylfurfural and 5-methylfurfural) were quantified using the HPLC method. Chromatic characteristics, colour sensory analysis and total polyphenol index were also analysed. Fourier transform near-infrared spectroscopy (FT-NIR) was used to discriminate between samples. The results emphasized the favourable effect of oak wood contact on enhancing the colour and enriching AUS with low molecular weight compounds (LMWC). AUS aged in medium toasted wood exhibits high levels of total phenolic index, 5-hydroxymethylfurfural, furfural, coniferaldehyde, sinapaldehyde, sum LMWC and chromatic characteristics b* and C. Concentrations of syringaldehyde, ellagic acid, vanillin and syringic acid and a lighter colour (a* chromaticity coordinates) are higher in AUS aged with slightly more toasted wood. Nearly all analysed parameters showed an increase with ageing time. The FT-NIR technique allowed for the differentiation of aged AUS, focusing more on ageing time than on toasting level. Full article

The aim of this study was to evaluate the effects of mechanical (pigeage, délestage and remontage) and oxygenation treatments on the phenolic and aromatic compounds and sensory characteristics of Teran wines. The experiment included a 20-day maceration period, during which the above-mentioned treatments were applied, as well as the post-fermentation processes of pressing and first rack. The analysis of phenolic, chromatic and aroma compounds and the sensory characterization of the wines were used to describe the effects of the treatments investigated. After the observed maceration period, remontage resulted in wines with the highest total phenols (2682.0 ± 14.8 mg GAE/L). In contrast, délestage resulted in the lowest total phenols (2499.1 ± 17.6 mg GAE/L) and total anthocyanins (530.1 ± 2.8 mg/L) and had the strongest effects on chromatic characteristics. The post-fermentation processes (pressing, racking) showed similar trends and resulted in higher phenolic concentrations in the remontage wine, while the délestage was again characterized by lower total phenol and anthocyanin concentrations. In addition, the délestage wine contained a higher concentration of almost all analyzed esters and two higher alcohols (2-methylpropan-1-ol and 1-hexanol), while the remontage wine had the highest concentration of 2-phenylethanol and 3-methylbutyl acetate. Finally, maceration proved to be a key factor in defining the wines’ sensory characteristics, with the remontage-treated wine showing the best overall quality. Full article

This review aims to analyze the technological and scientific applications regarding cocoa fermentation through a prospective study of patent documents and research articles. The Espacenet database was used as a patent research tool by searching both the IPC code “A23G1” and the terms “cocoa” and “ferment*”. A total of 130 documents were found—49 were related to the subject. The Scopus database was also searched for scientific articles using the terms “cocoa” and “fermentation”. A total of 812 articles were found—517 were related to the subject. Cocoa fermentation has not yet reached technological maturity, despite the growth in patent documents and scientific research observed in the last two decades. The creation of the Cacao of Excellence Program (2009), among others, has incentivized sustainability and quality in cocoa-producing countries. Brazil, Colombia, and Indonesia are leading with scientific publications in the last 5 years, despite the lack of patents filed. The United Kingdom, France, China, Canada, and Germany, despite not being cocoa-producing countries, are the main holders of the technology. Patent documents analyzed relate to food science, biotechnology, engineering, and chemistry. Microbial biotechnology has gained attention as a key factor to produce a higher-quality cocoa bean. Saccharomyces is the most frequent genus of yeast used as a starter culture in patent documents. Some patent documents propose the addition of fruits during cocoa fermentation, but a few scientific studies have been found on the matter. Overall, technological applications and scientific studies have focused on improving cocoa quality. The cocoa market is expected to increase significantly in the next few years, representing an opportunity to develop high-quality cocoa using novel fermentation techniques. Full article

This study reports on the development of effective strain engineering strategies for the high-level bio-based production of coproporphyrin (CP), a porphyrin pigment compound with various applications, using Escherichia coli as a production host. Our approach involves heterologous implementation of the Shemin/C4 pathway in an E. coli host strain with an enlarged intracellular pool of succinyl-CoA. To regulate the expression of the key pathway genes, including hemA/B/D/E/Y, we employed a plasmid system comprising two operons regulated by strong trc and gracmax promoters, respectively. Using the engineered E. coli strains for bioreactor cultivation under aerobic conditions with glycerol as the carbon source, we produced up to 353 mg/L CP with minimal byproduct formation. The overproduced CP was secreted extracellularly, posing minimal physiological toxicity and impact on the producing cells. To date, targeted bio-based production of CP by E. coli has yet to be reported. In addition to the demonstration of high-level bio-based production of CP, our study underscores the importance of identifying key enzymatic reactions limiting the overall metabolite production for developing differential expression strategies for pathway modulation and even optimization. This investigation paves the way for the development of effective metabolic engineering strategies based on targeted manipulation of key enzymes to customize engineered strains for effective large-scale bio-based production. Full article

Kuratsuki bacteria enter the sake production process and affect the flavor and taste of sake. This study compared gene expression in the sake yeast Saccharomyces cerevisiae in co-culture with kuratsuki Kocuria to that in monoculture. Among the 5922 genes of S. cerevisiae, 71 genes were upregulated more than 2-fold, and 61 genes were downregulated less than 0.5-fold in co-culture with kuratsuki Kocuria. Among the stress-induced genes, fourteen were upregulated, and six were downregulated. Among the fourteen upregulated genes, six were induced in response to replication stress. Although the G1 cyclin gene CLN3 was upregulated by more than 2-fold, eight genes that were induced in response to meiosis and/or sporulation were also upregulated. Fourteen metabolism-related genes, for example, the glyceraldehyde-3-phosphate dehydrogenase genes TDH1, TDH2, and TDH3, were downregulated by less than 0.5-fold in co-culture with kuratsuki Kocuria. The gene expression patterns of S. cerevisiae co-cultured with kuratsuki Kocuria differed from those co-cultured with lactic acid bacteria. Therefore, S. cerevisiae responded differently to different bacterial species. This strongly suggests that kuratsuki bacteria affect gene expression in sake yeast, thereby affecting the flavor and taste of sake. Full article

Hydrogen gas is attractive as a clean fuel source if it can be produced efficiently without relying on fossil fuels. Biohydrogen production using photosynthetic bacteria may enable environmentally friendly hydrogen production but is currently limited by factors such as low oxygen tolerance. In this study, we isolate a new strain of bacteria that can produce hydrogen under aerial-phase conditions compared with those under liquid-phase conditions in a nitrogen gas or an argon gas atmosphere. Bacterial strains were cultured from scrapings taken from a steel signboard. Investigation of the hydrogen production of the strains under aerial- and liquid-phase conditions and subsequent DNA sequencing led to identification of the bacterium Cereibacter sp. KGU-NF001. Aerial-phase conditions were achieved by filter membranes with the bacterial strains and placing the membranes on medium-soaked cotton wool. The gas atmosphere affected the behavior of the isolated bacterial strains under both aerial- and liquid-phase conditions. Cereibacter sp. KGU-NF001 showed promising oxygen tolerance and was able to maintain hydrogen production of 1.33 mL/mg/d even when the atmosphere contained 12% oxygen. Our findings illustrate that biohydrogen production may be achieved by photosynthetic bacteria under oxygen-containing aerial-phase conditions, indicating a possible pathway to help lower our reliance on fossil fuels. Full article

The lignin derivatives generated during pulping might be responsible for the suboptimal performance of anaerobic reactors during the treatment of pulping wastewater. However, the exact mechanisms by which these derivatives exert influence remain unclear. This study investigated the influence of lignin derivatives, simulated using humic acids (HAs), in anaerobic granular sludge (AnGS). Compared to the enzymes present during floc-bonding and granule-bonding, the HAs impeded the conversion of unhydrolyzed substrates into methane and caused considerable inactivation of free enzymes. Simultaneously, the HAs suppressed agglomeration and weakened the strength of the AnGS. Furthermore, calcium ions helped maintain the integrity of the sludge structure. Therefore, the inhibition of extracellular enzymes using lignin derivatives delays the methanation of unhydrolyzed substrates, resulting in a reduced biomass within AnGS reactors owing to sludge disintegration and biomass loss. This study serves as a reference for investigating the persistent risks originating from lignin derivatives associated with using anaerobic granular-sludge bed reactors to treat pulping wastewater. Full article

Mannosylerythritol lipids (MELs), one of the most promising biosurfactants (BS), are glycolipids produced by yeasts or fungi, which have great environmental performance and high compatibility with the human body. MELs, besides working as typical surfactants, can form diverse structures when at or above the critical aggregation concentration (CAC), reduce the surface tension of water and other solutions, and be stable over a wide range of conditions. Among others, MELs present antimicrobial, antitumor, antioxidant and anti-inflammatory activities and skin and hair repair capacity, which opens possibilities for their use in applications from cosmetics and pharmaceutics to bioremediation and agriculture. However, their market share is still low when compared to other glycolipids, due to their less developed production process and higher production cost. This review gathers information on the potential applications of MELs mentioned in the literature since 1993. Furthermore, it also explores the current strategies being developed to enhance the market presence of MELs, in parallel with the ones developed for rhamnolipids and sophorolipids. Full article

Growing butter markets, domestically and globally, provide opportunities for value-added variants of butter. Adding probiotics to butter could boosts its bioactivity; however, maintaining probiotic viability during storage is a major challenge. Mathematical analysis of probiotic population changes could help improve our understanding of how probiotics interact with butter and storage conditions. Two strains of probiotics in a 1:1 ratio as free cells or Whey Protein Hydrolysate–Maltodextrin (WPH-MD)-encapsulated cells, Lactobacillus acidophilus ATCC 4356 (LA5) and Bifidobacterium animalis ssp. lactis ATCC 27536 (BB12), were separately mixed into butter at 1% levels. Using analysis of covariance, a mathematical evaluation for probiotic population changes was performed by periodically determining viable counts, resulting in an adjusted R² value of 0.98 and demonstrating a strong relationship between the dependent variable (log₁₀ counts of probiotics) and independent variables (cell type, temperature of storage, and time of storage). After 21 days of storage, the number of free cells in butter dropped from 7.45 log₁₀ CFU/g to 0.56 log₁₀ CFU/g. On the other hand, it took 63 days for encapsulated cells to achieve 0.80 log₁₀ CFU/g at the same temperature. The same trend persisted at −18 °C, indicating that the WPH-MD encapsulant had a protective effect. Full article

Anaerobic digestion of waste-activated sludge (WAS) towards biogas recovery is constrained by the limited hydrolysis and inhibited acetogenesis steps that hinder subsequent energy recovery. This study employed Fe(VI)/S(IV) oxidation to enhance the WAS solubilization and coupled it with the syntrophic interaction of hydrogen-producing acetogen (HPA) and sulfate-reducing bacteria (SRB) to stimulate the successive procedure towards methane production. Results showed that the dosage ratio of HPA-SRB to WAS (H-S-W) with 1:1:50 outperformed with the highest methane production potential (11.63 ± 1.87 mL CH₄/(g VSS·d). Meanwhile, the efficient and sequential process from acetogenesis to methanogenesis stimulated by HPA-SRB was evidenced by a significant decrease of 30.2% in the acetate concentration. The microbial community structure further manifested the crucial role of HPA-SRB with increased abundance of Desulfobulbus (2.07%), Syntrophomonas (1.24%) and Smithella (1.63%), which stimulated acetophilic methanogen boost with Methanobacterium dominating with 77.51% in H-S-W₁₀₀. Furthermore, the positive syntrophic relationships among HPA-SRB and acetophilic methanogens towards methane production were confirmed via molecular ecological network and canonical correspondence analysis. This study highlighted the syntrophic cooperation of the mixed consortia of HPA and SRB on methane production based on Fe(VI)/S(IV) pretreatment and provided the theoretical and technical basis for the potential implementation of novel methanogenesis technology for WAS treatment. Full article

The effects of pineapple residue (PR) on fermentation quality, chemical composition, and bacterial community of corn straw (CS) silage were evaluated. CS was ensiled with 0% control group (CON), 15% (P1), 30% (P2), and 45% (P3) PR on a fresh matter (FM) basis for 45 days. P3 had lower dry matter (DM) and crude protein (CP) contents but higher ammonia-N (NH₃-N) content than the other three groups (p < 0.05). Compared with the other groups, P1 had lower a pH and higher lactic acid and acetic acid contents (p < 0.05). The lactic acid bacteria count in P1 was higher than in P2 and P3 (p < 0.05); the number of yeast in P2 was higher than in the other groups (p < 0.05). With the increasing proportion of PR addition, the relative abundance of Lactobacillus gradually increased, and the dominant genus in P3 was Acetobacter. In summary, the addition of PR can improve the quality of CS silage, and the optimum addition ratio for PR was 15% on a FM basis. Full article

The endo-1,4-β-xylanases (EC 3.2.1.8) are the largest group of hydrolytic enzymes that degrade xylan, the major component of hemicelluloses, by catalyzing the hydrolysis of glycosidic bonds β-1,4 in this polymer, releasing xylooligosaccharides of different sizes. Xylanases have considerable potential in producing bread, animal feed, food, beverages, xylitol, and bioethanol. The fungus Aspergillus tamarii Kita produced xylanases in Adams’ media supplemented with barley bagasse (brewer’s spent grains), a by-product from brewery industries. The culture extract exhibited two xylanase activities in the zymogram, identified by mass spectrometry as glycosyl hydrolase (GH) families 10 and 11 (GH 10 and GH 11). The central composite design (CCD) showed excellent predictive capacity for xylanase production (23.083 U mL⁻¹). Additionally, other enzyme activities took place during the submerged fermentation. Moreover, enzymatic saccharification based on a mixture design (MD) of three different lignocellulosic residues was helpful in the production of fermentable sugars by the A. tamarii Kita crude extract. Full article

A key goal in current research on industrial curdlan production is the expansion of carbon sources for fermentation. In this study, a recombinant bacterial strain, sp-AmyAXCC, capable of fermenting and synthesizing curdlan using dextrin as a carbon source, was produced via heterologous expression of IPTG-inducible α-amylase from Xanthomonas campestris NRRL B-1459 in Agrobacterium tumefaciens ATCC31749. External expression of the enzyme was confirmed by western blotting, and the expression levels of exogenous proteins during the fermentation process were monitored. Additionally, the properties of the curdlan product were characterized using attenuated total reflectance-Fourier transform infrared spectroscopy and X-ray diffraction. The recombinant strain produced curdlan at a titer of 30.40 ± 0.14 g/L, gel strength of 703.5 ± 34.2 g/cm², and a molecular weight of 3.58 × 10⁶ Da, which is 33% greater than the molecular weight of native curdlan (2.69 × 10⁶ Da). In the batch fermentation of sp-AmyAXCC with 12% dextrin as a carbon source, the titer of curdlan was 66.7 g/L with a yield of 0.56 g/g, and a productivity rate of 0.62 g/L/h at 108 h. The results of this study expand the substrate spectrum for Agrobacterium fermentation in curdlan production and provides guidance for further industrialization of curdlan production. Full article

Polyamide is a thermoplastic polymer widely used for several applications, including cables in offshore oil and gas operations. Due to its growing annual production worldwide, this poorly biodegradable material has been a source of pollution. Given this scenario, the need has arisen to develop environmentally friendly techniques to degrade this waste, and biotechnology has emerged as a possible solution to mitigate this problem. This study aimed to investigate the potential of Yarrowia lipolytica to biodepolymerize polyamide fibers (PAF). Microbial cultures were grown in shaken flasks containing different concentrations of PAF (0.5 and 2 g·L⁻¹) and in a bioreactor with and without pH adjustment. PAF mass loss was up to 16.8%, achieved after 96 h of cultivation in a bioreactor without pH adjustment. Additionally, NMR analyses revealed that the amorphous regions of PAF, which are more susceptible to depolymerization, were reduced by 6% during cultivation. These preliminary results indicate the biotechnological potential of Y. lipolytica to depolymerize PAF. Full article

This research investigates how different fermentation techniques using non-Saccharomyces yeast (Candida ethanolica Ce, Hanseniaspora guilliermondii Hg, Hanseniaspora thailandica Ht) and Saccharomyces cerevisiae (Sc) affect the synthesis of hesperidin, nobiletin, and other flavonoid and aromatic substances, which play a vital role in improving the overall quality of fruit wines due to their various biological properties. The combination of Sc:(Ce.Ht)-1:100 (Ce 0.5 × 10⁷ CFU/mL, Ht 0.5 × 10⁷ CFU/mL, Sc 1 × 10⁵ CFU/mL) yielded the highest hesperidin content at 4.12 ± 0.08 mg/L, followed by the Sc:(Ce.Hg)-1:1 (Ce 0.5 × 10⁷ CFU/mL, Hg 0.5 × 10⁷ CFU/mL, Sc 1 × 10⁷ CFU/mL) combination at 4.08 ± 0.06 mg/L. The highest nobiletin content was achieved by the (Hg.Ht)-10-Sc (Hg 0.5 × 10⁷ CFU/mL, Ht 0.5 × 10⁷ CFU/mL, Sc 1 × 10⁷ CFU/mL) combination, reaching 1.04 ± 0.05 mg/L, which was significantly higher than other multi-strain combinations. Additionally, the hesperidin content produced by the (Hg.Ht)-10-Sc combination was relatively high at 4.04 ± 0.02 mg/L, demonstrating a richness and complexity of aroma superior to that of fermentation with commercial yeast strains alone. The findings suggest that the (Hg.Ht)-10-Sc combination is the most effective multi-strain combination for increasing the levels of nobiletin and hesperidin in citrus wine, thereby enhancing the overall quality of the wine. These experimental results offer a promising approach for enhancing the quality of citrus wines and other fruit wines. Full article

Proteins are an abundant biopolymer in organic waste feedstocks for biorefining. When degraded, amino acids are released, but their fate in non-methanogenic microbiomes is not well understood. The ability of a microbiome obtained from an anaerobic digester to produce volatile fatty acids from the twenty proteinogenic amino acids was tested using batch experiments. Batch tests were conducted using an initial concentration of each amino acid of 9000 mg COD L⁻¹ along with 9000 mg COD L⁻¹ acetate. Butyrate production was observed from lysine, glutamate, and serine fermentation. Lesser amounts of propionate, iso-butyrate, and iso-valerate were also observed from individual amino acids. Based on 16S rRNA gene amplicon sequencing, Anaerostignum, Intestimonas, Aminipila, and Oscillibacter all likely play a role in the conversion of amino acids to butyrate. The specific roles of other abundant taxa, including Coprothermobacter, Fervidobacterium, Desulfovibrio, and Wolinella, remain unknown, but these genera should be studied for their role in fermentation of amino acids and proteins to VFAs. Full article

Sorghum (Sorghum bicolour (L.) Moench) is an emerging reliable alternative for mahewu production. The aim of this study was to evaluate the health-promoting compounds, physicochemical and microbiological properties of sorghum-based mahewu produced by different traditional brewers in Thohoyandou, South Africa. A total of 18 mahewu samples produced by six traditional brewers (TB1–TB6) were collected and compared for antioxidant, physicochemical, and microbiological properties. Commercial sorghum mahewu was used as a control sample. The total phenolic content of the mahewu samples varied from 27.37 to 65.89 GAE /g, with commercial mahewu having a lower value. The flavonoid content ranged from 0.18 to 0.30 GAE/g, and commercial mahewu had a higher value. The DPPH scavenging activity and FRAP of mahewu samples ranged from 44.62% to 49% and 1.47 to 2.36 mg GAE/g, respectively. Commercial mahewu had a higher DPPH value but a lower FRAP value. The pH of mahewu varied significantly, ranging from 3.38 to 3.66, but was within the acceptable range. The °Brix values varied from 9.68 to 17.49, with traditional mahewu samples having higher values than commercial mahewu. Total titratable acidity ranged from 0.63 to 1.17%. The viscosity ranged from 444.33 to 1297.00 cP, with commercial mahewu having a higher value. There was a significant variation in the color of the mahewu samples with respect to L*, a*, b*, C, Hue, and ΔΕ. The growth of yeasts and molds varied from 7.95 log₁₀ to 8.99 log₁₀ (cfu/mL) in traditional mahewu samples, and coliforms ranged from 3.68 to 5.96 log₁₀ (cfu/mL) and were not isolated in commercial mahewu. The total plate count ranged from 7.914 to 8.978 log₁₀ (cfu/mL). The microbiological results show that traditional brewers are meeting the legal limit and can increase their products for commercialization. Full article

The specific sensory properties attributed to distillates from different plum varieties are intricately linked to aromatic substances, fruit quality, and technology employed during production. This study compares four plum brandies, each made from a renowned plum variety: Presenta, Valjevka, Čačanská lepotica, and Čačanská rodná on a production scale. Analytical and sensory profiles were assessed using GC-FID, an available analytical method advantageous for monitoring industrial fruit distillate production. Between 71 and 85 analytes were detected in the distillates, with the Presenta plum distillate containing the highest number of substances. Statistically significant differences in analyte concentration between plum varieties (p < 0.05) were observed for 11 analytes. The comparison of analytical profiles and sensory evaluation revealed that a high concentration of 1-propanol, despite its negative sensory perception, significantly impacts the overall perception of a distillate, contrasting with substances like acetaldehyde and propyl acetate, which have positive sensory evaluations but lesser significance in content. Our work identified key compounds and procedures that can be used as benchmarks for production of plum brandy with positive sensory evaluation. These findings demonstrate the broad application potential of GC-FID in fruit distillate production as an independent tool for aromatic profile assessment and quality control. Full article

The use of machine learning and deep learning has become prominent within various fields of bioprocessing for countless modeling and prediction tasks. Previous reviews have emphasized machine learning applications in various fields of bioprocessing, including biomanufacturing. This comprehensive review highlights many of the different machine learning and multivariate analysis techniques that have been utilized within Chinese hamster ovary cell biomanufacturing, specifically due to their rising significance in the industry. Applications of machine and deep learning within other bioprocessing industries are also briefly discussed. Full article

Silage is the most important component of a ruminant diet and has important production and health significance in ruminant production. The aim of the research was to investigate how the mixed silage of Chinese cabbage waste and rice straw (mixed silage) impacts the fecal microorganisms and metabolites in Hu sheep using Illumina sequencing and metabolomic analysis. A total of 16 Hu sheep (8 rams and 8 ewes) weighing about 39 kg and 5.5 months old were used as experimental sheep and divided into two groups (4 rams and 4 ewes, n = 8) using the principle of randomized trials: the control group with peanut sprouts, corn husks, and sorghum husks as roughage and the silage group with the mixed silage as roughage. There were no significant differences in the average daily gain (ADG), dry matter intake (DMI), or feed conversion rate (FCR) between the control group and the mixed silage groups (p > 0.05). Microbiome results showed that 15 microorganisms such as Ruminococcaceae UCG 010, Breznakia, Erysipelothrix, Desulfovibrio, Succiniclasticum, and Shuttleworthia were significantly different between the two groups. In addition, metabolomics showed that the mixed silage modulated the concentrations and metabolic pathways of metabolites in the manure. Significantly different metabolites were mainly enriched in amino acid anabolism (“glycine, serine, and threonine metabolism”, “valine, leucine, and isoleucine biosynthesis”, “arginine biosynthesis”, etc.), nucleic acid metabolism (pyrimidine metabolism). In conclusion, the addition of mixed silage to the diet of Hu sheep can alter the structure of the hindgut microflora and regulate the metabolism of amino acids and nucleotides, which affects health performance. Full article

The discovery and biotechnological application of new antimicrobial peptides are impeded by a lack of sensitive methods for peptide quantification. Paenibacillin is an emerging antimicrobial lantibiotic that was discovered in Paenibacillus polymyxa OSY-DF ATCC PTA-7852, isolated from the fermented vegetable Kimchee. This lantibiotic has potency against many foodborne pathogenic and spoilage bacteria. To advance the research and application of paenibacillin, a rapid, specific, and sensitive detection and quantification immunoassay was developed. After anti-paenibacillin polyclonal antibodies (pAbs) were generated and purified, a competitive enzyme-linked immunosorbent assay (cELISA) was developed and optimized for paenibacillin quantification. The dynamic range of the cELISA was determined by using a three-parameter nonlinear regression model, achieving a correlation (R²) value of 0.95. The cELISA displayed high sensitivity, with the ability to detect paenibacillin at levels as low as 15.6 ng/mL, which is significantly lower than the limit of detection of the conventional antimicrobial assay (20 µg/mL paenibacillin). The cELISA successfully differentiated paenibacillin concentrations in cell-free crude supernatants of P. polymyxa wild type and its mutant strain when grown at 30 °C and 37 °C; higher paenibacillin levels were found in the mutant (0.248–0.276 µg/mL) than in the wild type (0.122–0.212 µg/mL) culture. These findings were validated by the transcriptional analysis of 11 paenibacillin biosynthetic genes, which were significantly upregulated (≥2-fold increase) in the mutant compared with the wild strain. Additionally, the cELISA exhibited high sensitivity by recovery of paenibacillin titers spiked at 2.5 and 10 µg/mL in de Man, Rogosa, and Sharpe (MRS) broth and diluted skim milk. These results suggest that the anti-paenibacillin pAbs and the developed cELISA could be valuable in quantifying paenibacillin in complex matrices and in aiding the discovery of paenibacillin-producing natural microbiota. Full article

The required processes and steps for making bread include technological and innovative concepts. The current trend is the use of less toxic compounds and green methods. Besides lactic acid bacteria and yeast, other microorganisms with unique properties, such as enzymes, new aromas and flavors, exopolysaccharides, and vitamins, among other compounds with beneficial properties, could be added to bread manufacture, improving bread quality and health effects for the consumers. The preservation of microbial cultures and starters is crucial in bread-making. New encapsulation methods, cryoprotectants, spray-drying, fluidized bed drying, and vacuum drying are employed for microorganism cultures that will be used as starters or biological additives in fermentation. A development is observed in the antimicrobial methods used as bread preservatives, and studies with plant extracts and essential oils have been proposed and introduced, replacing chemical agents, such as propionate, within the clean-label bread formulations concept. Baking science is a growing research line that incorporates innovative methods, biological additives, new methods, and processes focusing on microbiological protection. Full article

The enzyme-based degradation of lignocellulose for bioenergy production is an eco-friendly and sustainable approach. This study aimed to elucidate the enzymatic characteristics of endoglucanase (EGL), β-glucosidase (BGL), and xylanase (XYN) from Trichoderma guizhouence NJAU4742, and to explore the potential mechanisms underlying their synergistic degradation of different natural substrates. The results demonstrated that the three enzymes possessed remarkable high-temperature catalytic activity, broad pH adaptability, and responsiveness to different metal ions. The functional group absorption peaks of different substrates were shifted and altered after the synergistic action, particularly for C=O and O-H. Simultaneously, the crystallinity index of wheat straw, soybean straw, rice straw, and corn straw decreased by 7.40%, 2.37%, 20.60%, and 7.67%, respectively, compared to CK (natural straw). Additionally, the dense structure of different substrates was destroyed, and the inner parenchyma began to be exposed after the synergistic action, as observed by SEM. These findings offer valuable theoretical guidance for the development of lignocellulase applications. Full article