Isolation and molecular identification of cellulose/hemicellulose degrading bacteria from agricultural compost and determination of their hydrolytic potential

Abstract

Nine cellulolytic bacteria were isolated from agricultural residues compost on selective culture medium amended with cellulose (filter paper) as the sole carbon source. Five of the nine isolates (CX2, CX4, CX5, CX7 and CX9) were able to degrade both cellulose (CMC) and xylan in congo red agar plates. The five isolates were able to depolymerize the agricultural wastes, rice straw and sugarcane bagasse. CMC-ase and xylanase production by the five isolates were determined on rice straw and sugarcane bagasse. CX2 and CX9 exhibited the highest CMC-ase and xylanase production on both rice straw and sugarcane bagasse. Among the isolated strains, CX9 produced the highest CMC-ase activity (71 pKat ml−1) on rice straw, whereas CX9 produced the highest xylanase activity (7.83 nKat ml−1) on sugarcane bagasse. In general, higher CMC-ase and xylanase production was obtained on rice straw compared with sugarcane bagasse. According to the sequences of the 16 s rRNA genes, the five isolates were identified as: Paracoccus kondratievae strain GB (CX2 and CX4), Paracoccus communis (CX5), Bacillus australimaris (CX7) and Bacillus pumilus (CX9). The sequences of the 16S rRNA genes of five isolates were submitted to the gene bank.