1.4.4. Biological Pretreatment

Biological pretreatment is a spectacular accomplishment that encourages the generation of minimal to no hazardous material, an environmentally sustainable procedure with low energy usage and moderate operating conditions. Cellulases generated by bacteria and fungi will hydrolyze and degrade the crystalline structure of lignocellulosic biomass, increasing sugar yields and improving MFC efficiency [32]. *Clostridium*, *Cellulomonas*, *Bacillus*, *Termomonospora*, *Ruminococcus*, *Bacteriodes*, *Erwinia*, *Acetovibrio*, *Microbispora*, and *Streptomyces* are among the bacteria that may generate cellulases [33]. The drawbacks of this approach include the need for a longer retention period of 10 to 14 days, close monitoring of growth conditions to prevent contamination, and a significant amount of room for biological pretreatment, both of which render it less economically feasible. Krishnaraj et al. (2015) used a novel three-chamber MFC to produce bioelectricity while simultaneously decaying lignocellulosic biomass (sugarcane bagasse and corncob). In the first compartment of the three-chamber MFCs, *Oscillatoria annae* degraded the LCB. Anodic inoculums of *Oscillatoria annae* and *Gluconobacter roseus* were used to produce electricity in MFCs utilizing decomposed substrates from the first chamber. For sugarcane bagasse and corncob as substrates, the maximum PD was 8.78 W/m<sup>3</sup> and 6.73 W/m<sup>3</sup> , respectively [34].
