Novel pH control strategy for efficient production of optically active l-lactic acid from kitchen refuse using a mixed culture system

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

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Uninvestigated control factors of meta-fermentation, the fermentative production of pure chemicals and fuels in a mixed culture system, were examined for production of optically pure l-lactic acid (LA) from food waste. In meta-fermentations by pH swing control, l-LA production with 100% optical purity (OPl-LA) was achieved even using unsterilized model kitchen refuse medium with preferential proliferation of l-LA-producing Bacillus coagulans, a minor member in the seed, whereas agitation decreased OPl-LA drastically. pH constant control shortened the fermentation time but decreased OPl-LA and LA selectivity (SLA) by stimulating growth of heterofermentative Bacillus thermoamylovorans. Deliberately switching from pH swing control to constant control exhibited the best performance for l-LA production: maximum accumulation, 39.2 g L-1; OPl-LA, 100%; SLA, 96.6%; productivity, 1.09 g L-1 h-1. These results present a novel pH control strategy for efficient l-LA production in meta-fermentation based on a concept different from that of pure culture systems.

Original languageEnglish
Pages (from-to)52-59
Number of pages8
JournalBioresource Technology
Volume216
DOIs
Publication statusPublished - Sep 1 2016

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Environmental Engineering
  • Renewable Energy, Sustainability and the Environment
  • Waste Management and Disposal

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