Proteolysis produced within biofilms of bacterial isolates from raw milk tankers

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• 作者：Koon Hoong Teh^a ; ^b ; ^{k.teh@massey.ac.nz} ; Steve Flint^a ; Jon Palmer^a ; Paul Andrewes^b ; Phil Bremer^c ; Denise Lindsay^b
• 关键词：Biofilm ; Milk tanker ; Proteolysis ; Enzyme-producing bacteria
• 刊名：International Journal of Food Microbiology
• 出版年：2012
• 期刊代码：63_01681605
• 类别：abs
• 出版时间：15 June, 2012
• 卷：157
• 期：1
• 页码：28-34
• 文件大小：837 K

摘要

In this study, six bacterial isolates that produced thermo-resistant enzymes isolated from the internal surfaces of raw milk tankers were evaluated for their ability to produce proteolysis within either single culture biofilms or co-culture biofilms. Biofilms were formed in an in vitro model system that simulated the upper internal surface of a raw milk tanker during a typical summer's day of milk collection in New Zealand. The bacterial isolates were further evaluated for their ability to form biofilms at 25, 30 and 37 掳C. Mutual and competitive effects were observed in some of the co-culture biofilms, with all isolates being able to form biofilms in either single culture or co-culture at the three temperatures. The proteolysis was also evaluated in both biofilms and corresponding planktonic cultures. The proteolysis per cell decreased as the temperature of incubation (20-37 掳C) increased. Furthermore, mutualistic interactions in terms of proteolysis were observed when cultures were grown as co-culture biofilms. This is the first study to show that proteolytic enzymes can be produced in biofilms on the internal surfaces of raw milk tankers. This has important implications for the cleaning and the temperature control of raw milk transport tankers.