Isolation and characterization of a thermotolerant methanol-utilizing yeast.
A yeast capable of growth on methanol as its sole carbon-energy source was isoalted from soil samples and identified as a strain of Hansenula polymorpha. A continuous enrichment culture at 37 C with a simple mineral salts medium was used to select this organism. The isolate, designated DL-1, has a maximal specific growth rate of 0.22 per h, at pH 4.5 to 5.5 and temperatures of 37 to 42 C, in simple mineral salts medium with methanol (0.5%), biotin, and thiamine. Growth occurred in a chemostat at temperatures up to 50 C, with strong growth at 45 C. The maximal growth yield of the yeast on methanol was 0.36 g of dry cell weight per g of methanol, and the yield on oxygen was 0.37 g of dry cell weight per g of O(2). Protein content of the isolate is 46%, and total nucleic acid content varies from 5.0 to 7.0% with increasing growth rate from 0.08 to 0.20 per h. The amino acid profile of this yeast protein indicates that it could serve as a good source of food protein. Feeding studies with rats show the yeast to have no toxic effects.
D000596:Amino Acids / Q000032:analysis; D000821:Animal Feed; D000818:Animals; D001835:Body Weight; D003124:Colorimetry; D003470:Culture Media; D004044:Dietary Proteins; D005285:Fermentation; D005656:Fungal Proteins / Q000032:analysis / Q000633:toxicity; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008297:Male; D000432:Methanol / Q000378:metabolism*; D008851:Micropore Filters; D009696:Nucleic Acids / Q000032:analysis; D010101:Oxygen Consumption; D051381:Rats; D011919:Rats, Inbred Strains; D012988:Soil Microbiology; D013053:Spectrophotometry; D015003:Yeasts / Q000032:analysis / Q000254:growth & development* / Q000302:isolation & purification / Q000378:metabolism
D000596:Amino Acids; D003470:Culture Media; D004044:Dietary Proteins; D005656:Fungal Proteins; D009696:Nucleic Acids; D000432:Methanol