Effects of Surfactant Tween 80 on Enzymatic Accessibility and Degradation of Orchardgrass (Dactylis glomerata L.) at Different Growth Stages

Heterologous expression and characterization of a novel thermo-halotolerant endoglucanase Cel5H from Dictyoglomus thermophilum

A novel β-1,4-endoglucanase gene was cloned from Dictyoglomus thermophilum, designated as Cel5H for being a member of glycoside hydrolase family 5. The purified recombinant endoglucanase showed high hydrolytic activities on carboxylmethyl cellulose with a broad optimal temperature of 50-85°C and an optimal pH of 5.0. Furthermore, this enzyme was highly thermostable with a half-life of 336 h at 70°C and retained more than 80% of the initial activity after 135 days incubation at 50°C. To enhance the performance of the thermophilic endoglucanase, chimeric enzymes containing Cel5H and syncretic cellulose binding module (CBM) were constructed. The results showed that all the CBMs were effective. In addition, Cel5H was highly tolerant against high salt concentration and distinguished from salt-tolerant bacteria since it was independent of high salt concentration. Three-dimensional structure of Cel5H was developed by homology modeling methods and surface electrostatic analysis was performed.

Surfactant-enhanced anaerobic acidogenesis of Canna indica L. by rumen cultures

Polyoxyethylene sorbitan monoolate (Tween 80) was used to enhance the anaerobic acidogenesis of Canna indica L. (canna) by rumen culture in this study. Dose of Tween 80 at 1 ml/l enhanced the volatile fatty acids (VFA) production from the acidogenesis of canna compared to the control. However, Tween 80 at higher dosages than 5 ml/l inhibited the rumen microbial activity and reduced the VFA yield. Response surface methodology was successfully used to optimize the VFA yield. A maximum of VFA yield of 0.147 g/g total solids (TS) added was obtained at canna and Tween 80 concentrations of 6.3g TS/l and 2.0 ml/l, respectively. Dosage of Tween 80 at 1-3.75 ml/l reduced the unproductive adsorption of microbes or enzymes on the lignin part in canna and increased microbial activity. A high VFA production was achieved from canna presoaked with Tween 80, suggesting that the structure of canna was disrupted by Tween 80.