title: Study on regulation of growth and biosynthesis of cellulolytic enzymes from newly isolated Aspergillus fumigatus ABK9.
abstract: This study was aimed to evaluate the pattern of cellulase biosynthesis from Aspergillusfumigatus ABK9 under submerged fermentation. Production was increased concomitantly with fungal growth up to 72 h and reached maximum (Xmax -6.72 g/l) with specific growth rate (mu max) of 0.126/h. Highest specific rate of enzyme production (q ) was found at initial medium pH of 5.0 and incubation temperature of 30 degrees C. At the same time, in the presence of 2-deoxy-D-glucose concentration of 0.5 mg/ml, the production of cellulolytic enzymes, viz, carboxymethyl cellulase activity (CMCase), filter paper degrading activity (FPase) and P-glucosidase activity reached maximum of 132.2, 21.3 and 28.9 U/ml, respectively. Cellulase biosynthesis was induced in respect to higher volumetric production rate (Qp), specific rate of enzymes production (qp, U/g biomass/h) and enzyme/biomass yield (YE/X) when grown in carboxymethyl cellulose in comparison to other saccharides as sole carbon source. Induction ratios (IR) of cellulases were between 12.3 and 24.4 in the presence of 1.5% (w/v) CMC in the culture media. The strain was quite resistant to catabolic repression by glucose up to 0.4% (w/v). Cellulases production was greatly influenced in the presence of yeast extract and potassium dihydrogen phosphate (KH2POA) as nitrogen and phosphate sources in the culture media. C/N ratio of 10.0 and C/P ratio of 4.0 proved to be the best for the production of enzyme cocktail. Along with the high production yield, the crude enzymes showed a promising cellulose hydrolyzing efficiency of rice straw, indicating the enzyme could be beneficial for its large scale industrial exploitation.
authors.affiliation: Department of Microbiology, Vidyasagar University, West Bengal, India.
authors.forename: Arpan
authors.initials: A
authors.lastname: Das
authors.forename: Tanmay
authors.initials: T
authors.lastname: Paul
authors.forename: Suman Kumar
authors.initials: SK
authors.lastname: Halder
authors.forename: Chiranjit
authors.initials: C
authors.lastname: Maity
authors.forename: Pradeep Kumar
authors.initials: PK
authors.lastname: Das Mohapatra
authors.forename: Bikash Ranjan
authors.initials: BR
authors.lastname: Pati
authors.forename: Keshab Chandra
authors.initials: KC
authors.lastname: Mondal
mesh_terms: D001232:Aspergillus fumigatus / Q000145:classification* / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D002244:Carbon; D002480:Cellulase / Q000235:genetics / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D003847:Deoxyglucose; D005285:Fermentation; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D009584:Nitrogen; D012275:Oryza; D010758:Phosphorus; D010802:Phylogeny; D018547:Plant Stems / Q000378:metabolism; D013696:Temperature
chemical_list: D010758:Phosphorus; D002244:Carbon; D002482:Cellulose; D003847:Deoxyglucose; D002480:Cellulase; D009584:Nitrogen