Extraction of Lignocellulolytic Enzymes and Phylogenetic Analysis of
Fungi from Spent Mushroom Compost
Abstract
Spent mushroom compost (SMC) has highly rich lignocellulosic contents
like paddy straw, bagasse, chicken manure, etc.; hence, it is a natural
source of lignocellulolytic enzymes (LCE) secreted by its microflora and
microbiota. An effective procedure was optimised in the present
investigation to recover LCE from SMC. Maximum yield of the recovered
enzymes was attained with extraction in distilled water at 4
○C±2 ○C with uniform agitation for
60 minutes. Enzymes extracted were subjected to concentrating by
tangential flow filtration quantified as 1022.2±4.9IU
carboxymethylcellulase and 17.5±0.09IU laccase activity. pH stability
study of lyophilised extracted enzyme powder at 30 ○C
showed that extract reconstituted in sterile distilled water has a
constant and stable activity for up to 24 hrs. The study also confirmed
that pH 6.0-8.0 is optimum for cellulase and pH 4.0 for laccase
activity. Further, heterogeneous cultures isolated from SMC were
subjected to understanding the diversity and phylogenetic relationship
of microbes in SMC, which was carried out by internal transcribed spacer
identification. Filtrate culture (FC) was found to be closely related to
Suhomyces xylopsoci. The most abundant strains detected based on
percent identity were S. xylopsoci, Candida xylopsoci, and
Pichia kudriavzevii, with 99.2% in FC. Similarly, residue
culture (RC) was closely related to Wickerhamomyces sydowiorum. P.
myanmarensis, and W. edaphicus with 82.9% identity in RC. These
mixed cultures are primarily responsible for extracellular cellulase and
laccase production, which belongs to the lignocellulolytic group of
enzymes. This optimised protocol provides optimal conditions for
extracting stable active enzymes with few novel insights on
LCE-secreting organisms like S. xylopsoci and W.
sydowiorum.