Monday, July 25, 2011: 10:00 AM
Grand Chenier, 5th fl (Sheraton New Orleans)
Methane is a potential greenhouse gas and its negative effect on ecosystem is 21 times greater than carbon monoxide. On the other hand, huge quantities of agricultural by-products (such as rice straws) that produced annually are polluting the environment because they are not being fully utilized or properly disposed off. Lovastatin is the secondary product of Fungi and it is inhibitor of HMH-COA reductase (key enzyme in the cholesterol production pathway in human and cell membrane formation in archaea). In this study, rice straw was used as substrate for A. terreus (ATCC74135) to produce lovastatin for inhibition of methanogenesis as well as improving the quality of rice straw as ruminant feed. In the first experiment, different factors were optimized for lovastatin production in solis state fermentation. Maximum production of lovastatin using the optimize conditions was 247.05 mg kg-1DM. The solid state fermentation reduced concentrations of NDF, ADF, cellulose and hemicelluloses in the rice straw compared to the control. The fermentation process also significantly enhanced the crude protein content, antioxidant activity and free fatty acid content of the rice straw. Effect of lovastatin and methanol extracts from the fermented rice straw (contain lovastatin) on pure culture of methanogenic bacteria was investigated in a following experiment. Results showed that both extract and lovastatin were able to significantly reduce the methane production and methanogenesis in methanogenic bacteria tested. The results of gene expression studies showed that both lovastatin and extract significantly reduced the expression of the genes related to the methanogenesis.