Newly isolated and characterized bacteria with great application potential for decomposition of lignocellulosic biomass.

ABSTRACT

This study focuses on the isolation and characterization of bacteria from municipal waste and peat to determine those bacteria with good potential for modification and decomposition of lignocellulosic biomass for industrial application. Twenty cellulase-producing bacteria belonging to four major phyla - Firmicutes, Actinobacteria, Proteobacteria and Bacteroidetes - were found when screened on carboxymethyl cellulose-containing agar. Six isolates also exhibited activities towards filter paper as the sole carbon source in salt media, while 12 exhibited activities towards xylan when screened on xylan-containing plates. Moreover, 5 isolates survived in and increased the absorbance of 1% black liquor in salt media by an average of 2.07-fold after 21 days of incubation. Similarly, these 5 isolates increased the absorbance of 0.1% pure lignin at 280 nm in salt media, indicating modification of lignin. Additionally, the Fourier transform infrared spectroscopy analysis of 1% barley straw treated for 21 days with these 5 strains showed a preference for consumption of hemicelluloses over lignin; however, a change in lignin was observed. A Bacillus strain (55S5) and a Pseudomonas strain (AS1) displayed the greatest potential for lignocellulose decomposition due to a variety of cellulase activities, as well as xylanase activity and modification of lignin. Several of these isolates have good potential for industrial use in the degradation of lignocellulosic biomass.