Isolation of pullulanase-producing microorganisms of biotechnological interest

CAMINATA LANDRIEL, SOLEDAD; COSTA, HERNÁN; BERTONERI,AGOSTINA; CASTILLO DE LAS MERCEDES JULIETA; ANSELMO, RICARDO

Paraná

Congreso; LIV Reunión Anual de la SAIB; 2018

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Microorganisms are essential for obtaining enzymes due to their low cost of production and genetic engineering possibilities. There is strongbiotechnological interest in microbial enzymes applicable in food processing, agriculture, pharmaceutical industry and molecular biology.Bioprospecting describes the procedure of exploration, extraction, screening and trading of new products using biological diversity as source.Different enzymes are involved in processes related to the synthesis and degradation of α-glycosidic bonds. Pullulanases are a type of glycosidehydrolase debranching enzymes, which act on α-1,6 bonds of starch and other α-glucans like pullulan, consisting essentially of maltotriosyl unitsconnected by α-1,6 bonds. Pullulanases are widely used in the saccharification process to obtain useful products such as maltose, amylose andglucose by debranching starch; so, they are highly employed in the production of high-fructose corn syrup and in the starch processing industry.The aim of this work was to explore, isolate and identify aerobic bacteria producing enzymes acting on pullulan. By bioprospecting samples ofsoil and high starch-containing vegetables, 40 bacterial isolates were obtained, of which 3 secreted pullulan-hydrolytic enzymes. Bacteria wereidentified as Bacillus firmus, Alcaligenesfaecalisand Micrococcus luteus. HPLC analysis of the products of hydrolysed pullulan with isolatedenzymes showed maltotriose as the main product. Accordingly, these enzymes were classified as pullulanases. In particular, pullulanase isolatedfrom B. firmus produced the highest debranching activity.