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PLoS One

Title:		Assessment of beta-D-glucosidase activity and bgl gene expression of Oenococcus oeni SD-2a
Author(s):		Li Y; Wang Y; Fan L; Wang F; Liu X; Zhang H; Zhou J;
Address:		"Institute of Agro-product Processing, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China. School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China"
Journal Title:		PLoS One
Year:		2020
Volume:		20201009
Issue:		10
Page Number:		e0240484 -
DOI:		10.1371/journal.pone.0240484
ISSN/ISBN:		1932-6203 (Electronic) 1932-6203 (Linking)
Abstract:		"Glycosidases enhance flavor during wine-making by mediating the enzymatic release of aroma molecules. In order to better understand the aroma enhancement potential of Oenococcus oeni SD-2a, beta-D-glucosidase (betaG) activities in the culture supernatant, whole cells, and disrupted cell lysate were assessed at mid log, late log and stationary growth phase. The enzymatic activity was also compared further from cell cultures with 5 different carbon sources (glucose, cellobiose, arbutin, glucose and cellobiose, glucose and arbutin) at late log phase. Correspondingly, expression levels of 3 bgl genes, OEOE-0224, OEOE-1210, and OEOE-1569 were investigated from cell cultures of the 3 growth phases, and the 5 cell cultures with different carbon sources. Finally, the volatile aroma compounds released by O. oeni SD-2a in synthetic wines with natural glycosides were evaluated by GC-MS. Results showed betaG of O. oeni SD-2a was not extracellular enzyme, and the location of it didn't change with the change of growth phase and carbon source studied. betaG activities in the whole cells and disrupted cell lysate were similar and constant at the 3 growth phases. As for the carbon sources, betaG activities of whole cells and disrupted lysate were positively affected by cellobiose. While arbutin displayed positive and negative effect on betaG activity of whole cells and disrupted lysate, respectively. It is probably that bgl genes OEOE-0224 and OEOE-1210 were related to betaG activity of SD-2a whole cells, while OEOE-1569 was responsible for betaG activity of disrupted lysate. More kinds of volatile compounds and higher total concentration were released by SD-2a in synthetic wine compared with control. Thus, SD-2a showed a great potential for flavor enhancement under wine-like conditions. This study provides more information for further study of betaG activity from O. oeni SD-2a"
Keywords:		"Bacterial Proteins/genetics/metabolism Carbon/metabolism Fermentation Gas Chromatography-Mass Spectrometry Gene Expression Regulation, Bacterial Gene Expression Regulation, Enzymologic Oenococcus/enzymology/genetics/*growth & development Volatile Organic;"
Notes:		"MedlineLi, Yahui Wang, Ying Fan, Linlin Wang, Fan Liu, Xiaoli Zhang, Hongzhi Zhou, Jianzhong eng Research Support, Non-U.S. Gov't 2020/10/10 PLoS One. 2020 Oct 9; 15(10):e0240484. doi: 10.1371/journal.pone.0240484. eCollection 2020"