DEVELOPMENT OF INCREASED ACETIC-ACID TOLERANCE IN ANAEROBIC HOMOACETOGENS THROUGH INDUCED MUTAGENESIS AND CONTINUOUS SELECTION

Effective methods for large scale mutagenesis of strictly anaerobic, thermophilic microorganisms were developed. Mutagenesis and selection were carried out under highly reduced conditions without using plating techniques. Ultraviolet light (u. v. ) or ethyl methanesulphonate (EMS) produced similar improvements in acetic acid tolerance of Clostridium thermoaceticum. An additive effect was observed when u. v. and EMS were applied simultaneously. N-Methyl-n-nitro-N-nitrosoguanidine was ineffective.