Blattel V.,Institute of Microbiology and Wine Research |
Larisika M.,Institute of Microbiology and Wine Research |
Larisika M.,AIT Austrian Institute of Technology |
Pfeiffer P.,Institute of Microbiology and Wine Research |
And 5 more authors.
Applied and Environmental Microbiology | Year: 2011
During vinification microbial activities can spoil wine quality. As the wine-related lactic acid bacterium Pediococcus parvulus is able to produce slimes consisting of a β-1,3-glucan, must and wine filtration can be difficult or impossible. In addition, the metabolic activities of several wild-type yeasts can also negatively affect wine quality. Therefore, there is a need for measures to degrade the exopolysaccharide from Pediococcus parvulus and to inhibit the growth of certain yeasts. We examined an extracellular β-1,3-glucanase from Delftia tsuruhatensis strain MV01 with regard to its ability to hydrolyze both polymers, the β-1,3-glucan from Pediococcus and that from yeast cell walls. The 29-kDa glycolytic enzyme was purified to homogeneity. It exhibited an optimal activity at 50°C and pH 4.0. The sequencing of the N terminus revealed significant similarities to β-1,3-glucanases from different bacteria. In addition, the investigations indicated that this hydrolytic enzyme is still active under wine-relevant parameters such as elevated ethanol, sulfite, and phenol concentrations as well as at low pH values. Therefore, the characterized enzyme seems to be a useful tool to prevent slime production and undesirable yeast growth during vinification. Copyright © 2011, American Society for Microbiology. All Rights Reserved.
Polag D.,Institute of Earth science |
May T.,Institute of Microbiology and Wine Research |
Muller L.,DBFZ German Biomass Research Center |
Konig H.,Institute of Microbiology and Wine Research |
And 3 more authors.
Bioresource Technology | Year: 2015
Effective control of anaerobic digestion in biogas plants requires the monitoring of process sensitive and rapid response parameters in order to ensure efficient biogas production and to prevent potential process failure. In this study, stable carbon isotopes of methane (δ13CCH4) produced in a full-scale continuous stirred-tank reactor were investigated as a potential new monitoring tool for this purpose. Over a six-month period with variable organic loading rates, δ13CCH4-values were measured online by a portable high-precision laser absorption spectrometer. During a stress period of consecutive high organic loading, δ13CCH4-values early indicated process changes in contrast to traditionally monitored parameters where a change was observed some five to ten days later. Comparison of the stable isotope values with data from microbial analyses showed a distinct relationship between the quantity of potentially acetoclastic methanogens and δ13CCH4-values. This finding indicates an association between dominant methanogenic pathways and carbon isotope values. © 2015 Elsevier Ltd.