%0 Journal Article
%T Production of Pectate Lyase by Penicillium viridicatum RFC3 in Solid-State and Submerged Fermentation
%A Viviani Ferreira
%A Roberto da Silva
%A D那nis Silva
%A Eleni Gomes
%J International Journal of Microbiology
%D 2010
%I Hindawi Publishing Corporation
%R 10.1155/2010/276590
%X Pectate lyase (PL) was produced by the filamentous fungus Penicillium viridicatum RFC3 in solid-state cultures of a mixture of orange bagasse and wheat bran (1ˋ:ˋ1ˋw/w), or orange bagasse, wheat bran and sugarcane bagasse (1ˋ:ˋ1ˋ:ˋ0.5ˋw/w), and in a submerged liquid culture with orange bagasse and wheat bran (3%) as the carbon source. PL production was highest (1,500ˋUˋ or 300ˋ of substrate) in solid-state fermentation (SSF) on wheat bran and orange bagasse at 96 hours. PL production in submerged fermentation (SmF) was influenced by the initial pH of the medium. With the initial pH adjusted to 4.5, 5.0, and 5.5, the peak activity was observed after 72, 48, and 24 hours of fermentation, respectively, when the pH of the medium reached the value 5.0. PL from SSF and SmF were loaded on Sephadex-G75 columns and six activity peaks were obtained from crude enzyme from SSF and designated PL I, II, III, IV, V, and VI, while five peaks were obtained from crude enzyme from SmF and labeled , , , , and . Crude enzyme and fraction III from each fermentative process were tested further. The optimum pH for crude PL from either process was 5.5, while that for PL III was 8.0. The maximum activity of enzymes from SSF was observed at , but crude enzyme was more thermotolerant than PL III, maintaining its maximum activity up to . Crude enzyme from SmF and PL showed thermophilic profiles of activity, with maximum activity at 60 and , respectively. In the absence of substrate, the crude enzyme from SSF was stable over the pH range 3.0每10.0 and PL III was most stable in the pH range 4.0每7.0. Crude enzyme from SmF retained 70%每80% of its maximum activity in the acid-neutral pH range (4.0每7.0), but PIII showed high stability at alkaline pH (7.5每9.5). PL from SSF was more thermolabile than that from SmF. The latter maintained 60% of its initial activity after 1ˋh at . The differing behavior of the enzymes with respect to pH and temperature suggests that they are different isozymes. 1. Introduction The pectinolytic enzyme group includes protopectinases that degrade insoluble pectin, esterases that catalyse the de-esterification of pectin by removing the methoxyl esters groups and depolymerases that cleave - ( -) glycosidic bonds by hydrolysis and transelimination mechanisms. The lyases break down the glycosidic bonds of the pectates or pectins at C-4 and eliminate H from C-5, releasing a 4,5-unsaturated product [1]. These enzymes belong to various classes: pectate disaccharide lyase (exopectate lyase〞ExoPGL) E.C. 4.2.2.9, pectin lyase (Endo-pectin lyase〞EndoPMGL) E.C. 4.2.2.10,
%U http://www.hindawi.com/journals/ijmicro/2010/276590/