ANAEROBIC PHENOL DEGRADATION BY MICROORGANISMS OF SWINE MANURE

Swine manure contains diverse groups of aerobic and anaerobic bacteria . An anaerobic bacterial consortium containing sulfate-reducing bacter ia (SRB) and acetate-utilizing methanogenic bacteria was isolated from swine manure, This consortium used phenol as its sole source of carbo n and converted it to methane and CO2. The sulfate-reducing bacterial members of the consortium are the incomplete oxidizers, unable to carr y out the terminal oxidation of organic substrates, leaving acetic aci d as the end product. The methanogenic bacteria of the consortium conv erted the acetic acid to methane. When a methanogen inhibitor was used in the culture medium, phenol was converted to acetic acid by the SRB , but the acetic acid did nor undergo further metabolism. On the other hand, when the growth of SRB in the consortium was suppressed with a specific SRB inhibitor, namely, molybdenum tetroxide, the phenol was n ot degraded. Thus, the metabolic activities of both the sulfate-reduci ng bacteria and the methanogenic bacteria were essential for complete degradation of phenol.