In silico phylogenetic analysis of fungal lipase genes and harnessing the inherent potential of Aspergillus niger IBP2013 for extracellular triglycerol acyl-hydrolase production under solid state fermentation

摘要

Mesophilic fungi have evolved inherently thermostable/thermophilic enzyme production potentials over the years. To explore this potential, fungal colonies were isolated from rotten food items and screened, based on their extracellular triglycerol acyl-hydrolase (lipase) potential over lipid-rich agro-wastes. Hyper-lipase producing fungus was identified by comparing with standard fungal morpho-graphs as Aspergillus niger ( A. niger ) IBP2013. In present study, coconut meal was found a potential medium for fungus to produce higher extracellular lipase enzyme (lipase activity (la), 23.7±0.25 U/mL min -1 ; lipase specific activity (lsa), 97.4 U/mg) under solid state fermentation. This inherent potential of the fungus was enhanced up to 41.1±0.4 U/mL min -1 (la) and 169.5 U/mg (lsa) by eco-cultural optimization like substrate (coconut meal) and adequate concentrations (10g), inoculum level (1mL), incubation period (72h), temperature (40o C) and pH (7). Moreover, the concentrations of organic (peptone, 1% w/v) and inorganic nitrogen (ammonium acetate, 1% w/v) and carbon (lactose, 0.8% w/v) supplements were found essential for optimal lipase production. Three known fungal genes ( Lip1 , Lip2 and Lip3 ) were utilized for in silico phylogenetic analysis. Hence, A. niger IBP2013 with optimized cultural conditions could be potential candidate for lipase production at commercial scale.