Microbial degradation of Pyrazine Compounds in Wastewater and cow dung SouthwestNigeria.

Abstract

Wastewater samples, industrial effluents from food industry and cow dung were obtained aseptically and the physico-chemical properties were determined following standard procedures. Serial dilution technique was used in isolating native pyrazine - degraders from composite wastewater and cow dung samples obtained from Agbara and Apapa wastewater treatment plant (WTP) as well as Agege and Agbara Abattoirs respectively. Nutrient agar and Mineral salt medium supplemented with (3%) Pyrazine-2-carboxamide were used for enrichment for the isolates. Standard and conventional methods were used for the characterization and identification of pyrazine degraders. Gas chromatography (GC) flame ionization detector (FID) was used to determine the degree of mineralization of pyrazine. The mean pyrazine-degrader count from wastewater samples was 1.1×106 cfu/ml while that of cow dung was 9.7×105 cfu/ml. The GC peaks revealed that the initial quantity of pyrazine (15mg/l) was mineralized leaving behind (0.175mg/l) residues after 21 days of its introduction. The bacterial genera found utilizing pyrazine as source of C and N energy includes; Bacillus sp.,Flavobacterium sp.,Corynebacterium sp., Pseudomonas sp.,Streptococcus sp. and Staphylococcus sp. The biodegradability of pyrazine by tropical indigenous bacterial consortium was established and the convincing evidence of its mineralization was with gas chromatography. The objectives of the current study was to isolate and identify indigenous pyrazine-degraders from tropical wastewater and cow dung.