Isolation of thermophilic l-lactic acid producing bacteria showing homo-fermentative manner under high aeration condition

Saowanit Tongpim, Ratchanu Meidong, Pramod Poudel, Satoshi Yoshino, Yuki Okugawa, Yukihiro Tashiro, Masayuki Taniguchi, Kenji Sakai

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

By applying non-sterile open fermentation of food waste, various thermotolerant l-lactic acid-producing bacteria were isolated and identified. The predominant bacterial isolates showing higher accumulation of l-lactic acid belong to 3 groups of Bacillus coagulans, according to their 16S rRNA gene sequence similarities. B.coagulans strains M21 and M36 produced high amounts of l-lactic acid of high optical purity and lactic acid selectivity in model kitchen refuse medium and glucose-yeast extract-peptone medium. Other thermotolerant isolates resembling to Bacillus humi, B. ruris, B.subtilis, B. niacini and B. soli were also identified. These bacteria produced low amounts of l-lactic acid of more than 99% optical purity. All isolated strains showed the highest growth rate at temperatures around 55-60°C. They showed unique responses to various oxygen supply conditions. The majority of isolates produced l-lactic acid at a low overall oxygen transfer coefficient (KLa); however, acetic acid was produced instead of l-lactic acid at a high KLa. B.coagulans M21 was the only strain that produced high, consistent, and reproducible amounts of optically pure l-lactic acid (>99% optical purity) under high and low KLa conditions in a homo-fermentative manner.

Original languageEnglish
Pages (from-to)318-324
Number of pages7
JournalJournal of Bioscience and Bioengineering
Volume117
Issue number3
DOIs
Publication statusPublished - Mar 1 2014

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology

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