Estudo da produção de biopolímero e biomassa pelo fungo L. theobromae mmpi em meio à base de melaço de cana-de-açúcar empregando delineamento fatorial

Abstract

Exopolysaccharides are microbial polymers produced and excreted into the growth medium. These biomolecules have biotechnological properties that instigate the interest in the chemical, pharmaceutical and food industries. The production of exopolysaccharides in growth medium of low cost is an economic strategy for the success of the bioproduction process. In the present study the molasses sugar cane was evaluated as a substrate for the biotechnological production of exopolysaccharide lasiodiplodan. Factorial design central rotational compost 23 was used as a statistical tool to assess the influence of variables: concentration of molasses (1,0; 3,5 e 6,0 ºBrix), initial pH (4,0; 6,0 e 8,0) of the growth culture and speed stirrer (50, 125 e 200 rpm) on production, yield and volumetric productivity in exopolysaccharides and cell biomass, no significant effects were observed (range 90% confidence) on levels of the variables evaluated on production, yield and productivity in biopolymers. However, higher production values (8,880 g L-1), yield (0,588 g g-1) and volumetric productivity on EPS (0,123 g L-1 h-1) were observed in the levels of the central point (3,5 ° Brix, pH 6,0 and 125 rpm). Moreover, in the confidence interval of 90% were observed significant main effects and interaction effects of variables on production, yield and volumetric productivity on cell biomass. The higher biomass productions (9,845 g L-1) and volumetric productivity on biomass (0,136 g L-1h-1) was observed when applied molasses sugar cane of 6,0 °Brix, 200 rpm of speed stirrer and pH 4,0. Already the maximum yield of cell biomass (8.62 g g-1) was observed when concentration of substrate were of 1,0 ° Brix, pH 4.0 and stirrer speed at 200 rpm.