Correlating lignocellulose converting enzymes, substrate utilization and biological efficiency of Pleurotus eryngii strains grown on different agricultural residues

Abstract

In the present investigation, P. eryngii strain-substrate specificity, lignocellulolytic enzyme production and substrate utilization was correlated with the biological efficiency on different agricultural residues. Three strains of P. eryngii (DMR-P-120, DMR-P-135, DMR-P-257) were evaluated on low cost, easily available lignocellulosic agricultural wastes (wheat straw, paddy straw, maize stalks and soybean straw) in solid state fermentation for correlating the enzyme activity with yield potential of the strains. In the linear race tube growth studies, the mycelial extension rate increased with increase in days of incubation upto 28 days. Among all the substrates, maize stalks supported maximum mycelial extension rate (8.29 mm/day) for strain DMR-P-257 followed by wheat straw (7.86 mm/day) for strain DMR-P-257, soybean straw (6.71 mm/day) for strain DMR-P-120 and paddy straw (5.57 mm/day) for strain DMR-P-135 at 3rd week. A common trend was observed for the cellulolytic complex i.e. endoglucanase, exoglucanase, β-glucosidase, xylanase and laccase from the crude enzyme extracts and found that soybean straw showed the highest activity while paddy straw showed the least enzyme activity. Cultivation trials conducted for the three strains of P. eryngii on best performing substrates from race tube experiment viz. maize stalks and wheat straw for correlating lignocellulolytic enzymes at different morphological stages and biological efficiency. Among the growth stages, fruiting body stage showed highest lignocellulolytic enzyme activity. DMR-P-257 strain gave highest biological efficiency (36.18%) on wheat straw. Thus, the present study suggested that agricultural wastes could be used as a low-cost substrate for producing lignocellulosic enzyme activities which can be correlated for optimizing the best substrate for improving the yield potential of mushrooms.