Yeast Extract Promotes Cell Growth and Induces Production of Polyvinyl Alcohol-Degrading Enzymes

Min Li,Dongxu Zhang,Xianyan Liao,Guocheng Du,Jian Chen

doi:10.4061/2011/179819

Min Li, Dongxu Zhang + Show 3 more

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https://doi.org/10.4061/2011/179819

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Abstract

Polyvinyl alcohol-degrading enzymes (PVAases) have a great potential in bio-desizing processes for its low environmental impact and low energy consumption. In this study, the effect of yeast extract on PVAases production was investigated. A strategy of four-point yeast extract addition was developed and applied to maximize cell growth and PVAases production. As a result, the maximum dry cell weight achieved was 1.48 g/L and the corresponding PVAases activity was 2.99 U/mL, which are 46.5% and 176.8% higher than the control, respectively. Applying this strategy in a 7 L fermentor increased PVAases activity to 3.41 U/mL. Three amino acids (glycine, serine, and tyrosine) in yeast extract play a central role in the production of PVAases. These results suggest that the new strategy of four-point yeast extract addition could benefit PVAases production.

Highlights

Polyvinyl alcohol (PVA), a water-soluble synthetic polymer, has commercial applications in the adhesive, paper-coating, and textile industries [1,2,3]
VM15C is the combination of a PQQ-dependent PVA dehydrogenase (PVADH) and oxidized PVA hydrolase (OPH) [16]
Yeast extract contains abundant of vitamins, minerals, and amino acids, which are necessary for cell growth and PVAases synthesis [22]

Summary

Introduction

Polyvinyl alcohol (PVA), a water-soluble synthetic polymer, has commercial applications in the adhesive, paper-coating, and textile industries [1,2,3]. The material is of interest for packaging applications, such as bags for dyeing shops, packaging of household items, packaging of monodoses for powders and solid tablets, as well as for liquid concentrates, monodose packaging of chemicals for agriculture such as pesticides, and herbicides [4]. It is one of the major water pollutants in industrial wastewater, especially in textile factory wastewater. Sakai et al reported that PVA was degraded by successive reactions of secondary alcohol oxidase and β-diketone hydrolase (oxidized PVA hydrolase) from Pseudomonas sp. PVADH and OPH constitute an enzyme system for the cleavage of PVA molecules. PVADH introduces β-diketone groups into the PVA molecule, and OPH subsequently hydrolyzes these β-diketone groups in oxidized PVA

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