Seaweed (Eucheuma cottonii) associated microorganisms, a versatile enzyme source for the lignocellulosic biomass processing

Abstract

Seaweeds are highly productive, macroscopic organisms inhabiting the marine environment which affords the shelter for a variety of microorganisms. However, the existence and functional significance of biofuel related enzyme producing bacterial groups are poorly understood. This study deals with the lignocellulosic biomass breakdown capability of the phylogenetically diverse microbial communities from the Eucheuma cottonii by their biofuel related enzymes. The lignocelluloses depolymerizing multi-enzyme complex, such as lignin peroxidase, xylanase and cellulases were present in all the 13 microbial isolates belonging to the genera Brachybacterium, Brevibacterium, Halomonas, Kokuria, Micrococcus, Nocardiopsis, Pseudomonas and Streptomyces. Their enzymatic saccharification level varied from 46 to 84% for the paddy straw and 48–83% for the biomasses of sorghum. The residual reducing sugar conversion rate was comparatively similar when ammonia pretreated and non-pretreated biomasses were subjected to enzymatic saccharification. Their efficient exo-, endo-acting cellulolytic and hemicellulolytic enzyme secretion in an active form is an emerging resource for the biofuel production by the potential of recycling the lignocellulosic biomasses.