Recent Trends in Biomaterials for Immobilization of Lipases for Application in Non-Conventional Media

Round 1

Reviewer 1 Report

The manuscript for a review “Recent trends in biomaterials for immobilization of lipases for application in non-conventional media” concerns an interesting topic but is not in a publishable shape.

Overall the manuscript is too much of a collection of loose facts and too little about conclusions that one can draw from the literature. The authors In the conclusions page 23 lines 686-694 do name some of the topics that they should and could actually address.

The introduction is short and to the point but already chapter 2 on lipases leaves out some of the recent literature discussing what a lipase actually is and how to define it. A nice review by Verger (Ben Ali, Y.; Verger, R.; Abousalham, A. Lipases or Esterases: Does It Really Matter? Toward a New Bio-Physico-Chemical Classification. In Lipases and Phospholipases: Methods and Protocols; Book Series: Methods in Molecular Biology; Sandoval, G., Ed.; Springer Science+Business Media: New York, NY, USA,2012; Volume 861, pp. 31–51.) and a recent paper in Catalysts (Catalysts 2020, 10, 308; doi:10.3390/catal10030308) should be quoted.

Then the authors go through a number of natural materials without really having a reason for grouping the carriers the way they do. The authors do not discuss the carriers in the context of their properties and then afterwards in a logic sequence discuss the immobilisation methods. Instead it reads a little like a lining up of abstracts. Additionally many of the reactions described are performed in organic solvents and here the equilibrium is highly dependent on the amount of water in the reaction, the water activity to be more correct, and carriers are known to influence this. In particular work from Gardossi on partitioning effects should be quoted: Chem. Soc. Rev., 2013, 42, 6262--6276. And of course also used to improve the discussion. Another aspect that is not well discussed is the recycling of the enzymes. What are the reasons for activity loss, the carrier or the enzyme?

The materials are in many cases also modified. One does wonder why this is not discussed in a systematic manner. Material X has this properties, to change them into those properties method A is used for other properties method B is used and then do this for all materials.

Additionally one noticed that the recent rice husks that Gardossi introduced are missing while they are promising and would fit the criteria of the manuscript. See for instance: Catalysts 2018, 8, 471; doi:10.3390/catal8100471

In addition to this general criticism more detailed comments:

In fig. 3 anhydro not anydro

In figure 6 the linker with genipin seems rather unlikely. How should the genipin form the amide? It is more likely that the two aldehyde groups that are masked in the heterocycle form the linker.

Iine 294-296 the authors talk about a covalent bond between aminoacid residues, but this is not precise enough, the amino group or the acid group?

In lines 298 to 300 CALB on the carrier is mentioned with the stabilities. But these are not different to the normal CALB stability. This should be discussed. This lack of discussion is a reoccurring problem.

In Fig. 8 the reaction mechanism cannot be right. EDC activates acids and the activated acid then reacts with a nucleophile such as NHS. EDC normally does not activate primary alcohol. If this really is the case here it should be discussed why.

In fig. 12 and also in fig. 15 and 21 the circles for the active and reactive groups are not consistent and seem to have been scattered randomly.

 

Overall the manuscript needs to be reworked.

Author Response

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report

This review provides comprehensive information on lipases and its immobilized applications with recent discoveries in various reaction conditions that are crucial for catalytic activities. This manuscript touches on interesting subjects in the areas of biochemistry and bioorganic-chemistry. In addition, specific aspects of subjects including agarose, chitosan, cellulose, et al. are well categorized and explained with numbering. The references are also good guides for general readers.

I strongly recommend that the catalytic triad (amino acids inside enzymes) be depicted in Figure 2.

Some expressions and sentences need to be revised for proper English. 

Author Response

 

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The revised manuscript has been carefully reworked. The mechanism of the genipin linkage comes as a surprise but is well explained. The manuscript can now be accepted.