Production of molecular hydrogen and single cell protein by rhodopseudomonas capsulata from cow dung

Abstract

Anaerobically digested cow dung was separated by centrifugation into solid residue and supernatant fractions. The solid residue had 14.99% protein on a dry weight basis.This residue has been proposed to be a high quality feed supplement. The supernatant fraction, containing a considerable amout of volatile fatty acids, was fermented anaerobically with Rhodopseudomonas capsulata under illumination. Molecular hydrogen and biomass rich in protein (61.25% true protein) were the products of the fermentation. The protein consisted of appresiale amounts of essential and sulfur amino acids as compared to sovbean, egg and meat protein. Besides, an appreciably good amount of vitamin B₁₂ was formed in the biomass (28 μ g/g dry cells). The maximum hydrogen production rate achieved was 6.34 μ l/h/mg dry cells.