Isolation of xylose-utilizing lactic acid bacteria from Ariake Sea - Note

A screening test was carried out to obtain lactic acid bacteria utilizing xylose from bottom sediments in Ariake Sea as sources. About 100 xylose-utilizing bacterial isolates as acid producer were obtained from several sources. More than 50 isolates were catalase-negative and eight isolates produced more than 8 g/l lactic acid in MRS medium containing xylose at 20 g/l. The OTK-1 strain, which produced a high concentration of lactic acid (more than 12 g/l) was isolated from tideland in Ariake Sea. The OTK-1 strain was rod-shaped, as observed under a microscope. This strain was designated as Lactobacillus brevis OTK-1 on the basis of 16S rDNA sequence analysis. The maximum yield of produced lactic acid with respect to utilized xylose, and the lactic acid productivity were 1.15 mol/mol and 1.0 g/l/h, respectively. This strain was able to utilize xylooligosaccharide as a fermentative substrate.