TEMPERATURE AND PH DEPENDENCE ACTIVITY OF CRUDE ALCOHOL DEHYDROGENASE ISOLATED FROM YEAST (Saccharomyces cerevisiae) OF Raphia hookeri AND Elaeis guineensis SAPS IN SELECTED LOCATIONS IN NIGER DELTA REGION OF NIGERIA

Abstract

Alcohol dehydrogenase (E.C 1.1.1.1) is an enzyme that catalyses the reduction of acetaldehyde to ethanol during fermentation. In this study, the activity of crude alcohol dehydrogenase (ADH) isolated from yeast (Saccharomyces cerevisiae) of fresh Raphia hookeri and Elaeis guineensis palm wine(saps) from Niger Delta region (Akwa Ibom, Bayelsa, Cross River, Delta, Edo, Imo and River States) was determined at a temperature range of 25-70°C and pH 5.0-9.0. The results showed that the activity of alcohol dehydrogenase (ADH) of yeasts from both R. hookeri and E. guineensis palm saps increased in all the states as the temperature increased from 25-30oC but decreased with further increase in temperature from 40-700C. The optimum activity of the enzyme was recorded at an optimum temperature 300C for all the locations, with yeast ADH from Delta State exhibiting the highest activity (0.00025?mole/min). The study also showed that at various temperatures (30 -70°C), the ADH activities of yeasts isolated from E. guineensis sap were higher than those from R. hookeri sap. The activity of yeast ADH from R. hookeri sap in all the locations increased with increasing pH till 8.0 and declined markedly at pH 9.0. A similar trend was observed in the activity of yeast ADH from E. guineensis sap in all the states.The optimum pH of the enzyme was found to be 8.0 in yeasts from both R. hookeri and E. guineensis saps across all the locations. It is concluded that ADH from S. cerevisae isolated from R. hookeri and E. guineensis saps in the Niger-Delta region of Nigeria could be applied by alcohol-producing industries for alcoholic fermentation at an optimum temperature 30°C and pH 8.0, especially ADH from E. guineensis sap yeasts.