Biological production of ethanol from coal

Previously studies have shown the importance of both medium composition and concentration and medium pH on ethanol production of Clostridium ljungdahlii in fermenting CO, CO{sub 2} and H{sub 2} in synthesis gas. Four additional batch experiments involving medium composition and concentration were carried out in modified basal medium without yeast extract at pH 4.0. These experiments indicate that basal medium with only small amounts of B-vitamins can yield significant cell growth while yielding ethanol as the major product. Product ratios as high as 11.0 g ethanol per g acetate were obtained with half strength B-vitamins. Further experiments indicates that Ca-pantothenate may be necessary for the growth of C. ljungdahlii and that growth and ethanol production can occur simultaneously