Effects of isolated fungal pretreatment on bio-methane production through the co-digestion of rice straw and buffalo dung

Abstract

Fungal pretreatment is one of the most eco-friendly and less energy consuming method. Abundant species of fungus are accountable for degrading the roots. This study examined the influence of pretreatment of isolated fungal strains for methane production through co-digestion. Three different strains (Aspergillus niger, Aspergillus sojae, and Aspergillus terrerus) were identified from the rice plant roots after isolation. Strains were applied on same rice straw (RS) prior to use in anaerobic digestion at 7 d, 15 d and 30 d, named as group A, B and C respectively. Pretreated and untreated RS mixed with buffalo dung (BD) in a ratio of 30:70. Results indicated that pretreatment with A. terreus was most optimal in group B as compared with A. niger and A. sojae, whereas the methane production of 204.7, 181.3 and 167.6 mL CH4g-1VS was observed. While, maximum biodegradability (about 16.6%) was analyzed in the group C respectively. The Gompertz model show best fitted to experimental methane and the process even under biological conditions was statistically analyzed (p < 0.05). Thus, isolated fungus appears as a good potential strategy for increasing methane generation.