Enhanced delignification of lignocellulosic substrates by Pichia GS115 expressed recombinant laccase.

Enhanced delignification of lignocellulosic substrates by Pichia GS115 expressed recombinant laccase. J Gen Appl Microbiol. 2018 Apr 25;: Authors: Kumar VP, Kolte AP, Dhali A, Naik C, Sridhar M Abstract Utilization of energy-rich crop residues by ruminants is restricted by the presence of lignin, which is recalcitrant to digestion. Application of lignin degrading enzymes on the lignocellulosic biomass exposes the cellulose for easy digestion by ruminants. Laccases have been found to be considerably effective in improving the digestibility by way of delignification. However, laccase yields from natural hosts are not sufficient for industrial scale applications, which restricts their use. A viable option would be to express the laccase gene in compatible hosts to achieve higher production yields. A codon-optimized synthetic variant of Schizophyllum commune laccase gene was cloned into a pPIC9K vector and expressed in P. pastoris GS115 (his4) under the control of an alcohol oxidase promoter. Colonies were screened for G418 resistance and the methanol utilization phenotype was established. The transformant yielded a laccase activity of 344 U·mL-1 after 5 days of growth at 30°C (0.019 g·mL-1 wet cell weight). The laccase protein produced by the recombinant Pichia clone was detected as two bands with apparent molecular weights of 55 kDa and 70 kDa on SDS-PAGE. Activity staining on native PAGE confirmed the presence of bioactive laccase....
Source: Journal of General and Applied Microbiology - Category: Microbiology Tags: J Gen Appl Microbiol Source Type: research