Open L-lactic acid fermentation of food refuse using thermophilic Bacillus coagulans and fluorescence in situ hybridization analysis of microflora

• Published in: Journal of bioscience and bioengineering Vol. 101; no. 6; pp. 457 - 463
• Main Authors: Sakai, Kenji, Ezaki, Yutaka
• Format: Journal Article
• Language: English
• Published: Amsterdarm Elsevier B.V 01.06.2006; Elsevier Science; Elsevier Limited
• Subjects: 16S rRNA; ACIDE LACTIQUE; ACIDO LACTICO; APROVECHAMIENTO DE DESECHOS; BACILLUS COAGULANS; Bacteriocins - classification; Bacteriocins - genetics; Bacteriocins - isolation & purification; Bacteriocins - metabolism; Biological and medical sciences; Biotechnology; Colony Count, Microbial - methods; DECHET ALIMENTAIRE; DESECHOS ALIMENTARIOS; DNA, Bacterial - analysis; Feasibility Studies; FERMENTACION LACTICA; Fermentation; FERMENTATION LACTIQUE; FLORA MICROBIANA; FLORE MICROBIENNE; fluorescence in situ hybridization (FISH); Food Industry; Food Microbiology; food waste; FOOD WASTES; Fundamental and applied biological sciences. Psychology; In Situ Hybridization, Fluorescence - methods; Industrial Waste - prevention & control; kitchen refuse; L-lactic acid; LACTIC ACID; Lactic Acid - metabolism; lactic acid bacteria; LACTIC FERMENTATION; microbial analysis; MICROBIAL FLORA; open fermentation; Polyesters; Polymers - metabolism; Sewage - microbiology; Species Specificity; UTILISATION DES DECHETS; WASTE UTILIZATION; L-lactic acid; 16S rRNA; fluorescence in situ hybridization (FISH); kitchen refuse; lactic acid bacteria; food waste; open fermentation; microbial analysis; Lactic acid bacteria; Lactic fermentation; Microflora; Thermophily; Foodstuff; Bacillaceae; Bacillus coagulans; Food waste; Bacillales; Ribosomal RNA; Fluorescence in situ hybridization; 16S-RNA; Bacteria; Lactic acid; Microorganism
• ISSN: 1389-1723; 1347-4421
• DOI: 10.1263/jbb.101.457

In the production of commercially useful poly- L-lactic acid plastic from biomass wastes, a feasible fermentation process to produce optically active L-lactic acid would be required. Here, model kitchen refuse (MKR) was inoculated with Bacillus coagulans NBRC12583 under nonsterilized openculture conditions. At temperatures below 45°C, a racemic mixture of D- and L-lactic acids was accumulated, whereas only L-lactic acid was selectively accumulated by incubation at 50–65°C. At 45°C, the results of fermentation could not be consistently reproduced. To analyze microflora in this type of mixed culture system, whole-cell fluorescence in situ hybridization (FISH) using 16S rRNA-targeted oligonucleotide probes for B. coagulans, Bcoa191, and LAC722(L), a group-specific probe for a wide range of mesophilic lactic acid bacteria was applied. The dominancy of mesophilic lactic acid bacteria at lower temperatures, and that of B. coagulans at higher temperatures were confirmed. By using a saccharified liquid of collected kitchen refuse, 86 g/ l of L-lactic acid was accumulated under nonsterile conditions by a 5-d incubation at 55°C, pH 6.5, with 53% carbon yield and 97% optical purity. To conclude, high temperature open lactic acid fermentation is a simple and promising method for producing high-grade L-lactic acid from biomass waste, and FISH analysis of such mixed-culture systems is helpful for monitoring the microflora in these cultures.