Improving biogas production and biodegradability of acid hydrolytic cotton stalk with addition of nutritive salts and complex anaerobic cellulose decomposing bacteria

Nutritive salts and complex anaerobic cellulose decomposing bacteria (CACDB) were added for anaerobic digestion process in order to improve biogas production and biodegradability of acid hydrolytic cotton stalk. The results showed that addition of CACDB, nutritive salt land nutritive salt II could effectively enhance daily biogas production, cumulative biogas and methane yields, in this treatment, the total gas production, daily average gas production, TS gas production rate, VS gas production rate and average yield of methane were all highest and reached 5908.90 mL, 196.96 +/- 7.97 mL.d(-1), 143.07 +/- 5.79 mL.g(-1), 156.32 +/- 6.33 mL.g(-1), 102.58 +/- 3.34 mL.d(-1), separately. The addition of CACDB and nutritive salts could improve the biodegradability of acid hydrolytic cotton stalk, in all addition treatments, the degradation rates of cellulose and lignin, VS reduction rates were higher and C/N ratios were lower than control treatment. The SEM analysis showed that the microstructure changes of digestion residues were helpful for biogas production.