The Role of Lactic Acid Bacteria and its Application to Fermentation Processes by Ecosystem Engineering Approach.

1995 Fiscal Year Final Research Report Summary

• Project/Area Number: 06454036
• Research Category: Grant-in-Aid for General Scientific Research (B)
• Allocation Type: Single-year Grants
• Research Field: 生物・生体工学
• Research Institution: Osaka University
• Principal Investigator: SHIOYA Suteaki Department of Biotechnology, Faculty of Engineering. Osaka University, Professor., 工学部, 教授 (50026259)
• Co-Investigator(Kenkyū-buntansha): NAKAJIMA Mikio Department of Biotechnology, Faculty of Engineering. Osaka University, Assistant, 工学部, 助手 (00273590) ; SHIMIZU Hiroshi Department of Biotechnology, Faculty of Engineering. Osaka University, Associate, 工学部, 助教授 (00226250)
• Project Period (FY): 1994 – 1995
• Keywords: Lactic acid bacteria / Yeast / Synergic interaction / Propionic acid bacteria / Flowcytometry / Mixed culture / Antibiotic nisin

Research Abstract

In food fermentation and brewing processes, more than two species of microorganisms can be observed interacting with each other and the process is called as a mixed culture system. The tastes and flavors in foods and drinks made in fermentation processes are strongly correlated with the synergic interaction of these microorganisms. The aims of this research project are to analyze the synergic interaction of yeasts and lactic acid bacteria in whisky brewing process and to analyze and to control the production of a kind of autibiotics, nisin A,in a mixed culture system of lacti acid bacteria and propionic acid bacteria.
In whisky brewing process, the measurement method of the cell concentration by a flowcytometry was developed. Each cell concentrations of yeast and lactic acid bacterium could be accurately distinguished and measured quantitatively by PI and FITC labelling techniques, using the flowcytometer. Moreover, the role of yeast and lactic acid bacteria for, concerning with assimil ation of polysaccharide was analyzed. It has been reported that yeasts cannot assimilate some kinds of malto-oligosaccharides but lactic acid becteria can assimilate them. Thus, in this study, we investigated the ability for assimilation of malto-oligosaccharides by yeast and lactic acid bacteria. The lactic acid bacteria using in this study could not assimilate some kinds of malto-oligosaccharides, which could not be assimilated by yeasts. This result suggested the ability for the assimilation of the saccharides was strongly dependent on the strain.
The production of a kind of natural food preservation additives, antibiotic nisin A,by lactic acid bacterium was investigated. In order to avoid the addition of acid and alkaline for pH adjust, the mixed culture of nisin A producing lactic acid bacterium and propionic acid bacterium was performed. In the mixed culture system, the lactic acid produced by lactic acid bacterium was assimilated by propionic acid bacterium. Finally, the production of nisin A was increased two times higher by the mixed culture, comparing with the pure culture of lactic acid bacterium without pH control.