Production of yeast‐lytic enzymes by Cytophaga species in batch culture

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Section: Introductionmentioning

confidence: 99%

The isolation of lytic enzymes from Cytophaga and their application to the rupture of yeast cells

Asenjo

Dunnill

1981

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Synthesis and regulation of extracellular β (1–3) glucanase and protease by cytophaga sp. In batch and continuous culture

Andrews¹,

Asenjo²

1986

Lytic enzyme systems with the ability to break whole cells of yeast are a mixture of several enzymes and virtually all contain beta(1-3)glucanases and some protease. It appears that the presence of these two enzyme activities is necessary to break the two layers of the rigid cell wall. The enzyme system of Cytophaga NCIB 9497 has a high activity towards the walls of yeast and also of bacteria. This article describes the production of this extracellular lytic enzyme system in batch and continuous culture-it was found to be inducible. The synthesis and regulation of the two main constituent enzymes, beta(1-3)glucanase and protease, have been investigated. The synthesis of beta(1-3)glucanase is regulated by bothinduction (by an unknown inducer) and catabolite repression. Highbeta(1-3)glucanase activities were obtained in continuous culture at low dilution rates over a narrow range (0.05-0.10 h(-1)), and there is evidence of the presence of more than one glucanase enzyme. Proteolytic activity appears subject to catabolite repression and made up of the activities of more than one protease enzyme. Productivity and enzyme concentration were increased several fold in continuous culture when compared to batch culture.

Enhanced disruption of Candida utilis using enzymatic pretreatment and high‐pressure homogenization

Baldwin

Robinson

1994

The enhancement of the overall disruption of a native strain of Candida utilis (ATCC 9226) was studied using a combination of two methods, namely, pretreatment in the form of partial enzymatic lysis by Zymolyase followed by mechanical disruption in a Microfluidizer high-pressure homogenizer. The cells were grown in both batch and continuous cultures to examine the effect of specific growth rate on disruption. Cell suspensions ranging in concentration from 7 to 120 g DW/L were disrupted with and without enzymatic pretreatment. For yeast grown in batch culture, final total disruption obtained using the combined protocol approached 95% with four passes at a pressure of 95 MPa, as compared with only 65% disruption using only mechanical homogenization. A modified model was developed to predict the fraction disrupted by the enzymatic pretreatment-mechanical homogenization two-stage process. Predicted disruptions agreed favorably with experimental observations (maximum deviation of 20%) over a wide range of operating conditions. (c) 1994 John Wiley & Sons, Inc.