Production of single cell protein from methanol

Abstract

A $\mbox{\underline{Methanomonas}}$ Sp. that can utilize methanol as a sole carbon source has been isolated from the local soil samples in Korea. By using this organism, a continuous fermentation process was developed for the production of single cell protein. For this process, the medium and the process operating conditions have been optimized for the maximum biomass productivity by using continuous culture technique. This organism is gram-negative rod, 0.5 to 1.0 ㎛ wide and 1.5 to 2.0 ㎛ long, and occurs in pair. The maximum specific growth rate of this organism was 0.4 $hr^{-1}$ at PH 7.3 and 30 ℃. In a carbon-and nitrogen-limited chemostat, yield coefficient for carbon source and nitrogen source were 0.4 gram-cell per gram-methanol and 6.79 gram-cell per gram-ammonia respectively at a dilution rate of 0.2 $hr^{-1}$. The maximum biomass productivity obtained was 0.62 gram-cell/ liter-hour at a dilution rate of 0.2 $hr^{-1}$. Protein content of the single cell protein produced by this process was 71.5%, and amino acid profile in terms of the essential amino acid was as good as or better than FAO standard for food protein.