Characterization of cellulolytic activities of environmental bacteria

NELSON ROMANO; A. GIOFFRÉ; E. CAMPOS; A. CATALDI; P. TALIA

Mar del Plata

Congreso; VIII Congreso de Microbiología General; 2012

SAMIGE

The production of cellulolytic enzymescapable of converting lignocellulose into fermentable sugars is the main problem to the production of bioethanol from lignocellulosic biomass. In this context, our group has been working to obtain novel genes and microorganisms that degrade lignocellulose. The objective of this work is the identification and characterization of novel bacteria with cellulolytic activity. from Biotechnology Institute-INTA Castelar collection, obtained from soil (A1, A2, A3) and water samples (A4) and three cellulolytic bacterial consortia (more than one genus was identified by 16S rRNA sequencing),denominated CH2, CH3 and CH4. These consortia had been previously isolated and identified in our laboratory from native forest soil sample from Chaco, Argentina. Growth conditions and cellulolytic activity (ß-1,4 endoglucanase and total cellulase) were optimized. These cellulolytic activities were measured quantitatively and qualitatively. Carboxymethyl cellulose (CMC) degradation produced by the isolated was tested on solid medium by Congo red dye, as described by Theather and Wood (1982). A zone of clearance around the colonies was indictive of CMC degradation. We observed that A1 and the three bacterial consortia (CH2, CH3 and CH4) showed CMC hydrolysis. However, this activity was not detected in A2, A3 and A4. The diameter of the zone of clearance surrounding the colony in CMC 0.5% for A1 was 12±0.7mm; for CH2 (Achromobacter Pseudomonas), 3.4±0.8mm; for CH3 (Achromobacter), 9.2±0.7 mm and for CH4 (Achromobacter, Pseudomonas sp.), 7.3±0.7mm. Characterization of the ß-1,4 endoglucanase and total cellulase activities were performed in culture supernatants and cellular pellets as described by King et al. (2008), with modifications. As expected, enzymatic activity was observed in culture supernatants but not in the cellular fraction. In this study, we have identified and characterized for the first time the cellulolytic activity of environmental mycobacteria isolate. Moreover, we have showed that the mycobacterium isolate (A1) and the bacterial consortia encode for cellulolytic enzymes that could be useful tool in lignocellulosic biomass degradation into sample components for the subsequent use in ethanol production.