Studies on the Biochemical Characterization of Cold Active Cellulases From Pseudogymnoascus Roseus BPF6 and Their Potential Application in Simultaneous Saccharification and Fermentation of Selected Plants Biomass

Abstract

Cellulases from submerged culture of psychrophilic fungus Pseudogymnoascus roseus, partially purified by 40-50% ammonium sulfate saturation showed maximum FPase activity (0.278 U ml-1) at 40oC and pH 5.0, with metal sensitivity (Ca2+ ion causing 89% inhibition). The enzyme CMCase or endocellulase exhibited 100% activity at 30oC with 90% activity at 20oC and two peak activities at pH 5, and pH 11 and extremely metal sensitivity with Ca2+ causing nearly 40% inhibitions. The enzyme cellobiases yielded 100% of the activity at 4oC, and showed gradual decline at higher temperature. The enzymes showed two peak activities one major at pH 11 (100%) and other minor at pH 8 (80%). The enzyme was also metal sensitive with nearly 35 % of inhibition by Ca2+. It showed glucose inhibition above 4 % concentration. It was least inhibited by lactose (about 30%) and maximum by others viz., glucose, xylose, maltose and cellobiose (about 60%). The cocktail of enzymes could saccharify on the third day wheat straw, saw dust, A. excelsa, and rice straw to release glucose at 190 mg l-1, 63 mg l-1, 140 mg l-1 and 120 mg l-1 respectively. The calculated values of saccharification of various substrates was for wheat straw, saw dust, Ailanthus excelsa wood and rice straw were 85.5%, 63 %, 58.5 % and 54 % respectively. Under SSF 10 g of pretreated biomass with enzymes and yeast cells produced ethanol 2.1 gg-1, 1.6 gg-1, 1.3 gg-1 and 1.2 gg-1 using wheat straw, An excelsa, rice straw and saw dust respectively. newline