CELLULOLYTIC ACTIVITIES OF A NOVEL Cellulomonas flavigena ISOLATE. ACTIVIDADES CELULOLÍTICAS DE UN NUEVO AISLAMIENTO DE Cellulomonas flavigena.

PICCINI F.E:; MURUA Y.; GHIO, S; TALIA P; RIVAROLA M; CAMPOS E

Cordoba

Congreso; XI CONGRESO ARGENTINO DE MICROBIOLOGÍA GENERAL SAMIGE 2015; 2015

Asociación Civil de Microbiología General SAMIGE

Lignocellulose degrading bacteria are important in many industries, such as feed and paper industries.They also show high potential as source of enzymatic extracts for scarification of cellulose in secondgeneration bioethanol production. We have isolated a Cellulomonas flavigena strain, which we namedB6, from forest soil, and characterized its cellulase and xylanase activities in cell-free culturesupernatants. It was found that both cellulases and xylanases were mainly active in a range of pHclose to neutral (5.5 to 8) and moderate temperature (between 40 and 60°C). Endoglucanase activitywas maximal at pH 7 and 50°C, while and xylanse activity was maximal at pH 6 and 60°C. The mainreaction products were determined by HPLC, and consisted in xylobiose and xylose for xylanaseactivity and cellobiose for cellulase activity, indicating that the enzymatic extract has the capacity forfull deconstruction of xylan but needs supplementation with beta-glucosidase activity for fulldeconstruction of cellulose. We have also obtained a draft version of the bacterial genome using theIllumina MiSeq sequencing platform. The data comprised 1.532.556 paired-end reads, with a length of500 bp. It was assembled in 512 contigs and annotated by the IGS Annotation Pipeline(http://ae.igs.umaryland.edu). The genome has 74.7% of GC, in accordance with the reference strainof Cellulomonas flavigena. We have identified 16 new glycosyl hydrolases belonging to the CAZY GHfamilies 6, 9, 48, 10, 11, 39 and 43, with a wide array of potential enzymatic activities, as well as 19unclassified glycosyl hydrolases. Surprisingly, no beta-glucosidases were identified in the firstannotation. A potential endoglucanase-xylanase belonging to GH6 family, had been previouslyidentified in the supernatant as differentially expressed when the culture was grown on cellulose. Thefull coding sequence was identified in the genome, amplified and cloned for recombinant expression.These results indicate the high potential of this novel strain of Cellulomonas flavigena as a source ofcellulolytic enzymes.