Saccharide production from methanol by transposon 5 mutants derived from the extracellular polysaccharide-producing bacterium Methylobacillus sp strain 12S
T. Yoshida et al., Saccharide production from methanol by transposon 5 mutants derived from the extracellular polysaccharide-producing bacterium Methylobacillus sp strain 12S, APPL MICR B, 54(3), 2000, pp. 341-347
A CH3OH-utilizing bacterium that has the ability to produce extracellular p
olysaccharide (EPS) was isolated from a soil sample, and was identified as
the obligate methylotroph Methylobacillus sp. strain 12S on the basis of it
s 16S. rDNA sequence and growth-substrate specificity. The EPS produced by
strain 12S was purified and the sugar composition was analysed by CC-MS and
HPLC to reveal that the EPS was a heteropolymer composed of glucosyl, gala
ctosyl, and mannosyl residues in the molar ratio 3:1:1. In order to produce
mono- and/or oligosaccharides by single-step fermentation from CH3OH, stai
n 12S was mutagenized by transposon 5. Among eleven EPS-deficient mutants,
three strains were found to accumulate significant amounts of reducing suga
rs in the media. The amounts of the reducing sugars produced by the mutants
(> ca. 700 mg glucose equivalent/l) were >11-22 times higher than those pr
oduced by the wild-type strain (<ca. 60 mg glucose equivalent/l). The CC-MS
analysis showed that all the mutants accumulated glucose, erythrose, threo
se and a disaccharide-like compound in the media.