title: Reduction and restoration of culturability of beer-stressed and low-temperature-stressed Lactobacillus acetotolerans strain 2011-8.
abstract: Lactic acid bacteria (LAB) are the most common beer-spoilage bacteria, regardless of beer type, and therefore pose significant problems for the brewing industry. The aim of this study was to investigate the viable, but putatively non-culturable (VPNC) state of the hard-to-culture beer-spoilage species, Lactobacillus acetotolerans. Upon prolonged contact with degassed beer, L. acetotolerans was found to show decreased culturability. After 17 subcultures in beer, 100-μL aliquots of the culture were no longer culturable on MRS agar until 14 days of incubation despite the presence of 10(5) viable cells, indicating that a large population of cells entered into a VPNC state. Furthermore, a significant reduction or even putative loss of culturability, but maintenance of viability, of L. acetotolerans could also be induced by storing the strain at 0 °C for 105 days. Adding catalase at a concentration of 1000 U/plate enabled the VPNC cells, both induced by beer subculture treatment and cold treatment, to regain culturability with a resuscitation time of 4 days and 3 days, respectively. Scanning electron microscopy results demonstrated that cells decreased in size and gradually changed morphology from short rods to coccoids when they entered the VPNC state. It was concluded that the difficulty in culturing the spoilage bacterium from brewery environments could be partly attributed the hard-to-culture or the viable, but non-culturable characteristic of this organism.
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, PR China; Technical Center, Zhujiang Brewery Co., Ltd., No.118, Modiesha Avenue, East Xingang Road, Guangzhou 510308, PR China; Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, Guangzhou 510640, PR China. Electronic address: fedengyang@163.com.
authors.forename: Yang
authors.initials: Y
authors.lastname: Deng
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, PR China.
authors.forename: Junyan
authors.initials: J
authors.lastname: Liu
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, PR China; Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, Guangzhou 510640, PR China.
authors.forename: Lin
authors.initials: L
authors.lastname: Li
authors.affiliation: Technical Center, Zhujiang Brewery Co., Ltd., No.118, Modiesha Avenue, East Xingang Road, Guangzhou 510308, PR China.
authors.forename: Huijing
authors.initials: H
authors.lastname: Fang
authors.affiliation: Technical Center, Zhujiang Brewery Co., Ltd., No.118, Modiesha Avenue, East Xingang Road, Guangzhou 510308, PR China.
authors.forename: Jingxia
authors.initials: J
authors.lastname: Tu
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, PR China; Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, Guangzhou 510640, PR China.
authors.forename: Bing
authors.initials: B
authors.lastname: Li
authors.affiliation: Technical Center, Zhujiang Brewery Co., Ltd., No.118, Modiesha Avenue, East Xingang Road, Guangzhou 510308, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.affiliation: Technical Center, Zhujiang Brewery Co., Ltd., No.118, Modiesha Avenue, East Xingang Road, Guangzhou 510308, PR China.
authors.forename: Huiping
authors.initials: H
authors.lastname: Li
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, PR China. Electronic address: zhenbo.xu@hotmail.com.
authors.forename: Zhenbo
authors.initials: Z
authors.lastname: Xu
mesh_terms: D001515:Beer / Q000382:microbiology*; D003080:Cold Temperature; D005516:Food Microbiology; D007778:Lactobacillus / Q000254:growth & development / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D050296:Microbial Viability; D008855:Microscopy, Electron, Scanning; D013312:Stress, Physiological
keywords: Beer-spoilage; Induction; Lactobacillus acetotolerans; Restoration; VPNC