Studies on the degradation of corn straw by combined bacterial cultures.

In this study, the combined bacteria (CB) were constructed by Phanerochaete chrysosporium, Trametes versicolor and Pleurotus ostreatus, which have a good ability to degrade lignocellulose, and the optimum degradation conditions and internal degradation mechanism of combined bacteria were investigated. The results showed that under conditions of temperature (32 °C), pH (3.5), solid-liquid ratio (10%), culture time (20 d), the degradation rates of lignin, cellulose and hemicellulose were 43.36%, 31.29%, 48.36%, respectively. The construction of combined bacteria significantly enhances the degradation ability of lignocellulose, and showed good correlation and coordination mechanism.

Influence of particle scattering on photo biochemical transformation process of direct absorption methane digester.

An outdoor anaerobic fermentation reactor loses a significant amount of energy due to heat dissipation to the surrounding environment. The digester of direct absorption biogas can effectively utilize solar energy and scattering of the medium to enhance reaction temperature, which can promote anaerobic fermentation of microorganisms. A numerical model for the direct absorption methane digester was established to investigate the mechanism of photo biochemical transformation. The average relative values of simulated results were 4.1% and 9.6%, indicating that the model can effectively simulate the heat transfer process of biogas slurry under solar irradiation. Decreasing the albedo and increasing the effect of forward scattering of small particles can improve the regenerative performance and biogas production of digester. Increasing the backward scattering effect of small particles limited biogas fermentation. Scattering distribution had bigger effects on the rates of biogas and propionic acid production than those of albedo.

Effect of different aerobic hydrolysis time on the anaerobic digestion characteristics and energy consumption analysis.

Aerobic hydrolysis of stover before anaerobic digestion is beneficial to improve the biodegradability of corn stover. Aerobic hydrolysis of corn stover at 43 °C was conducted to investigate the effects of hydrolysis time (0 h, 8 h, 16 h, and 24 h) on the degradation of lignocellulose from corn stover and material conversion. Further anaerobic digestion and energy consumption analysis with the digestion temperature of 36 °C were carried out. The accumulation rate of volatile fatty acids began to slow down after 16 h of hydrolysis, and the concentration of acetic acid reached 221.85 mmol/L at 24 h of hydrolysis. The degradation rate of lignocellulose was obviously increased after hydrolysis. When the hydrolysis time was 16 h, it reached the maximum cumulative methane production with 268.75 ml/g VS. In terms of biogas production and energy conversion efficiency, it is more appropriate to choose 16 h as hydrolysis time in biogas engineering.