Direct starch fermentation to l-lactic acid by a newly isolated thermophilic strain, Bacillus sp. MC-07

Pramod Poudel, Yukihiro Tashiro, Hirokuni Miyamoto, Hisashi Miyamoto, Yuki Okugawa, Kenji Sakai

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

A newly isolated Bacillus sp. MC-07 showed 99.2 % 16S rRNA gene sequence similarity with the Bacillus thermoamylovorans LMG 18084T. It demonstrated optimum and maximum growth temperatures of 50 and 62 °C, respectively. The ability of MC-07 to produce optically pure l-lactic acid via direct fermentation of starch without enzymatic hydrolysis was investigated at different pH values (6.0–8.0) by intermittent adjustments every 12 h. During batch fermentation in mineral salt medium containing 0.001 % yeast extract at pH 7.0, 20 g/L of soluble starch was utilized to produce 16.6 g/L l-lactic acid at 50 °C within 24 h of fermentation, with 100 % optical purity, 92.1 % lactic acid selectivity, and an l-lactic acid yield of 0.977 g/g. Direct starch fermentation at pHs 6.0, 6.5, 7.5, and 8.0 resulted in considerably lower concentrations of lactic acid than did at pH 7.0. Compared with B. thermoamylovorans LMG 18084T, the ability of strain MC-07 to produce l-lactic acid was superior.

Original languageEnglish
Pages (from-to)143-149
Number of pages7
JournalJournal of Industrial Microbiology and Biotechnology
Volume42
Issue number1
DOIs
Publication statusPublished - Jan 1 2015

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology

Fingerprint Dive into the research topics of 'Direct starch fermentation to l-lactic acid by a newly isolated thermophilic strain, Bacillus sp. MC-07'. Together they form a unique fingerprint.

Cite this