Qualitative analyses of lignocellulolytic enzymes produced by Emericella sp strain HST9 under diverse culture conditions

ABSTRACT

Aim: Optimization of cultural conditions for improved lignocellulolytic enzyme production by an ascomycete HST9 isolated from leaf and litter waste. Methodology: The fungus HST9 was isolated from leaf and litter waste collected from Chaudhary Charan Singh Haryana Agricultural University, Hisar, India. Culture experiments were conducted at different temperature, pH, incubation periods and aeration conditions. Effects of addition of different concentrations of various metal ions, different carbon complexes and nitrogen salts on enzyme production were also studied under submerged culture condition. Enzyme activities were measured by standard protocols using spectrophotometer. Results: HST9 grew well and produced optimum enzymes at 30oC on 7th day of incubation at stationary conditions and pH- 6. Overall enzyme activities decreased after addition of metal salts. Carboxymethyl cellulose (300 mg l-1) and alkali lignin (200 mg l-1) were observed to be the best carbon complexes for cellulolytic and ligninolytic activities. Ammonium sulfate was found to be a better nitrogen source compared to others. Under optimum conditions, different enzyme activities observed were 0.011 IU m l-1 FPase, 0.015 IU ml-1 CMCase, 6.5 IU m l-1 Lac, 57.5 IU m l-1 LiP and 4 IU ml-1 MnP. Molecular phylogenetic analysis of the strain confirmed that strain HST9 showed closeness with genus Emericella. Interpretation: Lignocellulolytic enzyme activity of Emericella isolate HST9 enhanced at optimum culture conditions, signifying that it can be used as a biological agent to degrade lignocellulosic waste.