Improvement of saccharification of native grass,Pennisetum sp.using cellulase from isolated Aspergillus fumigatus for bioethanol production:an insight into in silico molecular modelling,docking and dynamics studies

Lignocellulosic grass biomass is potential substrate for economical and sustainable bioethanol production.However,the processing cost of bioethanol that majorly includes the hydrolysis of cellulose by cellulases is still a major concern for its industrial production.Thus,knowledge on the sequence to the structural study of cellulase enzyme with consideration of its catalytic region can give important information for effective enzyme engineering and consequently towards enhanced bioethanol production from Pennisetum sp.Therefore,in this study,sequence conservativeness of different cellulosic site among a group of endoglucanase family of cellulase from previously isolated Aspergillus species has been determined.Furthermore,comparative molecular modeling of the endoglucanase from eight different Aspergillus species including Aspergillus fumigatus was conducted and the obtained structures revealed a high degree of difference in their conformational folds.Analysis from InterProScan revealed that the modeled endoglucanase has similar types of domains and share homology with protein family,such as glycoside hydrolase family-61 and fungal cellulose binding domain.Furthermore,molecular docking and interaction studies demonstrated the presence of residues in the endoglucanase of A.fumigatus viz.His20,His88,Asp96,Ala99,Ser100,Ser101,His102,His169,Glu170,Arg173,Glu178,and Tyr218 that are responsible in forming the substrate interaction.An interesting molecular phenomenon,i.e.,catalytic promiscuity has been noted for all the substrate bound complexes of A.fumigatus endoglucanase which also depicts the degree of ligand binding efficacy of the studied enzyme.The molecular interaction study,binding energy analysis and molecular dynamics simulation,demonstrated that heteromeric substrate XylGlc3 is more strongly interacting with the receptor enzyme.Overall,the present findings revealed that important amino acid residues can help in increasing the specificity of endoglucanase from A.fumigatus towards hydrolysis of Pennisetum sp.and other biomass that has an adequate amount of XylGlc3,for possible industrial applications.

A review of microbial laccase production and activity toward different biotechnological applications

Laccases are versatile enzymes that belong to the multi-copper oxidase family.This enzyme has several biotechnological applications because of its ablilty to oxidize a wide range of phenolic and non-phenolic substrates.However,their large-scale applicability in bioremediation and water treatment is hindered by high salt content and extreme pH values of the polluted media which also affects the stability,recovery and recycling of laccase.Apart from some bacteria,laccase is abundantly present in several lignin-degrading white-rot fungi viz.Ascomycetes,Deuteromycetes,and Basidiomycetes.Recently,lac-case has been employed in the development of biosensors as a medical diagnostic tool,biofuel cells,and in bioremediation purpose to remove herbicides,pesticides,and some toxic chemicals from the soil.However,most of the enzymes including laccase are normally unstable and susceptible to lose their activity over time.This might be avoided by maintaining the activity and lengthening the enzyme's lifespan through the use of appropriate immobilization procedures.The potential of laccase immobilized biocathodes for dye decolorization in microbial fuel cells has recently been studied.Immobilized laccase nanoparticles have potential uses as biocatalyst in the bioremediation of pollutants.In addition,advanced research considering microbial laccase has been conducted for its heterologous expression along with in silico protein engineering to attain maximum enzyme activity which can be potentially applied in different biotechnological sectors.Patent related to laccase also implied that this enzyme can be used as suitable catalyst for the production of promising anti-cancer drugs and even as a significant ingredient in cosmetics.