Industrial waste based compost as a source of novel cellulolytic strains and enzymes

Abstract

Ninety bacteria isolated from raw composting materials were screened for their cellulolytic activity on solid medium containing carboxymethylcellulose. The bacteria producing the highest cellulolytic activity levels were identified by 16S rRNA sequencing as Bacillus licheniformis strain 1, Bacillus subtilis subsp. subtilis strain B7B, Bacillus subtilis subsp. spizizenii strain 6, and Bacillus amyloliquefaciens strain B31C. Cellulase activity production by the most productive strain B. amyloliquefaciens B31C was optimized in liquid culture varying the carbon source. Comparison of growth curves of B. amyloliquefaciens B31C at temperatures from 28 to 47 °C indicated its thermotolerant nature. Moreover, analysis of time courses of cellulase activity production in this thermal range showed that increase of temperature from 28 to 37 °C causes an increase of cellulase activity levels. Investigating the enzymes responsible for cellulase activity produced by B. amyloliquefaciens B31C by proteomic analyses, an endoglucanase was identified. It was shown that the purified enzyme catalyzes carboxymethylcellulose's hydrolysis following Michaelis-Menten kinetics with a K(M) of 9.95 mg ml(-1) and a v(max) of 284 μM min(-1) . It shows a retention of 90% of its activity for at least 144 h of incubation at 40 °C and exhibits a range of optimum temperatures from 50 to 70 °C.

Isolation, Screening and Characterization of Cellulase Producing Bacterial Isolates from Municipal Solid Wastes and Rice Straw Wastes

“…Filamentous fungi are the major source of cellulases and hemicellulases [10] but the production costs of these enzymes are very high. Bacteria which have high growth rate and short generation time in compared to fungi have good potential to be used in cellulase production [11]. The furthermost potential importance is the ease with which bacteria can be genetically engineered.…”

Paenibacillus polysaccharolyticus sp. nov., a xylanolytic and cellulolytic bacteria isolated from leaves of Bamboo Phyllostachys aureosulcata

“…T was analyzed separately in CMC-or xylan-amended (5 g l À1 ) basal medium containing the following substances per litre: NaNO 3 , 1 g; K 2 HPO 4 , 1 g; KCl, 1 g; MgSO 4 , 0.5 g; yeast extract, 0.5 g; glucose, 1 g and agar, 17 g. Cultures were incubated for 72 h, and a positive result (formation of a clear halo) was ascertained by adding 0.1 % Congo red solution, incubating for 30 min, and washing with 5 M NaCl [18]. For scanning electron microscopy (SEM) studies, the sample was processed as per the methodology described by Bozzola and Russel [19] and the images were visualized using a S-2500C SEM (Hitachi).…”

Identification and Characterisation of a Pectinolytic Enzyme from Paenibacillus xylanolyticus

“…The DNA sequencing was conducted at Primm srl (Milan, Italy). The DNA sequences were determined and analysed as previously reported (Amore et al 2013) and compared to the GenBank nucleotide data library using the Blast software (NCBI 2014) to determine their closest phylogenetic relatives.…”