%0 Journal Article
%T Production of Pectinolytic Enzymes by the Yeast Wickerhanomyces anomalus Isolated from Citrus Fruits Peels
%A Mar¨ªa A. Martos
%A Emilce R. Zubreski
%A Oscar A. Garro
%A Roque A. Hours
%J Biotechnology Research International
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/435154
%X Wickerhamomyces anomalus is pectinolytic yeast isolated from citrus fruits peels in the province of Misiones, Argentine. In the present work, enzymes produced by this yeast strain were characterized, and polygalacturonase physicochemical properties were determined in order to evaluate the application of the supernatant in the maceration of potato tissues. W. anomalus was able to produce PG in liquid medium containing glucose and citrus pectin, whose mode of action was mainly of endo type. The supernatant did not exhibit esterase or lyase activity. No others enzymes, capable of hydrolyzing cell wall polymers, such as cellulases and xylanases, were detected. PG showed maximal activity at pH 4.5 and at temperature range between 40¡ãC and 50¡ãC. It was stable in the pH range from 3.0 to 6.0 and up to 50¡ãC at optimum pH. The enzymatic extract macerated potato tissues efficiently. Volume of single cells increased with the agitation speed. The results observed make the enzymatic extract produced by W. anomalus appropriate for future application in food industry, mainly for the production of fruit nectars or mashed of vegetables such as potato or cassava, of regional interest in the province of Misiones, Argentine. 1. Introduction Enzymes hydrolyzing pectic substances, which contribute to the firmness and structure of plant cells, are known as pectinolytic enzymes or pectinases. Based on their mode of action, these enzymes include polygalacturonase (PG), pectinesterase (PE), and lyases (pectinlyase (PL) and pectatelyase (PAL)). PG, PL, and PAL are depolymerizing enzymes, which split the ¦Á-(1,4)-glycosidic bonds between galacturonic monomers in pectic substances either by hydrolysis (PG) or by ¦Â-elimination (PL, PAL). PG catalyzes the hydrolytic cleavage of the polygalacturonic acid chain while PL performs a transeliminative split of pectin molecule, producing an unsaturated product. PE catalyzes the de-esterification of the methoxyl group of pectin, forming pectic acid [1, 2]. There are two types of PGases with different technological applications: exopolygalacturonases (exo-PG) that break down the distal groups of the pectin molecule, reducing chain length relatively slowly, and endopolygalacturonases (endo-PG) which act randomly on all the links in the chain, reducing molecular dimensions and viscosity more rapidly [3]. Pectinolytic enzymes play an important role in food technology, mainly in the processing of fruit juices and wines and in the maceration of plant tissue. Maceration is a process by which organized tissue is transformed into a suspension of
%U http://www.hindawi.com/journals/btri/2013/435154/