Produção de hidrolases por leveduras isoladas do trato digestório de insetos aquáticos

Abstract

The use of enzymes has been taking more and more space, being of extreme importance in several industrial sectors, such as in the food, textile, pharmaceutical, among others. The present work evaluated the production of hydrolases (amylase, cellulase, lipase and xylanase) in specific solid media by 30 yeast strains isolated from the digestive tract of fragile insects (Phylloicus, Triplectides, Nectopsyches and Conotelus). Positive results were obtained for amylase, lipase and xylanase. Only one strain Papiliotrema Laurentii (PON28.6) presented halo hydrolysis for both amylase and xylanase, showing an enzymatic index (IE) of 1.47 and 2.41, respectively. For lipase the strains Papiliotrema Laurentii (PON28.6), Rhodotorula mucilaginosa (TRIP5), Cryptococcus sp. 1 (LAG12.1), Rhodotorula mucilaginosa (PH42), Candida parazyma (CO26) e Lodderomyces elongisporus (PON11.3), showed IE hydrolyzing halo ranging from 1.56 to 2.67. The Papiliotrema Laurentii (PON28.6) line was selected to evaluate xylanase production in submerged fermentation, evaluating the effect of seven variables (pH, concentrations of xylan, yeast extract, peptone, KH2PO4, MgSO4 and NaNO3) through a Plackett-Burman (PB12). Only the variables MgSO4 and yeast extract were significant and were used in a complete delineation (DCCR). The two variables were significant (p <5%) with enzymatic activities varying from 0.018 to 0.191 U.mL-1, but with the obtained model it was not possible to obtain an optimal point for xylanase production in the range of the tested variables.