title: Enterococcus faecium QU 50: a novel thermophilic lactic acid bacterium for high-yield l-lactic acid production from xylose.
abstract: Production of optically pure lactic acid from lignocellulosic material for commercial purposes is hampered by several difficulties, including heterofermentation of pentose sugars and high energy consumption by mesophilic lactic acid bacteria. Here, we report a novel lactic acid bacterium, strain QU 50, that has the potential to produce optically pure l-lactic acid (≥99.2%) in a homofermentative manner from xylose under thermophilic conditions. Strain QU 50 was isolated from Egyptian fertile soil and identified as Enterococcus faecium QU 50 by analyzing its sugar fermentation pattern and 16S rRNA gene sequence. Enterococcus faecium QU 50 fermented xylose efficiently to produce lactic acid over wide pH (6.0-10.0) and temperature ranges (30-52°C), with a pH of 6.5 and temperature of 50°C being optimal. To our knowledge, this is the first report of homofermentative lactic acid production from xylose by a thermophilic lactic acid bacterium.
authors: Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan Botany and Microbiology Department, Faculty of Science (Boys branch), Al-Azhar University, PN:11884, Nasr City, Cairo, Egypt.
authors: Mohamed Ali
authors: MA
authors: Abdel-Rahman
authors: Laboratory of Soil Microbiology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Japan, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan Institute of Advanced Study, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors: Yukihiro
authors: Y
authors: Tashiro
authors: Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors: Takeshi
authors: T
authors: Zendo
authors: Laboratory of Soil Microbiology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Japan, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors: Kenji
authors: K
authors: Sakai
authors: Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan Laboratory of Functional Food Design, Department of Functional Metabolic Design, Bio-Architecture Center, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan sonomoto@agr.kyushu-u.ac.jp.
authors: Kenji
authors: K
authors: Sonomoto
mesh_terms: D018533:Biomass; D004534:Egypt; D016984:Enterococcus faecium / Q000302:isolation & purification / Q000378:metabolism*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000378:metabolism*; D008031:Lignin / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012988:Soil Microbiology; D013696:Temperature; D014994:Xylose / Q000378:metabolism*
chemical_list: D012336:RNA, Ribosomal, 16S; C036909:lignocellulose; D019344:Lactic Acid; D008031:Lignin; D014994:Xylose
keywords: Lactate fermentation; biomass utilization; biorefinery; high temperature; homofermenters; pentose