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The experiment was to study the preparation of forage grade wheat oligopeptide by dual enzymatic method. The peptide content of food grade protease and feed grade protease was compared, and the best compound enzyme was selected. On basis of single factor experiment, orthogonal experiment was used to optimize enzymolysis conditions and determine the content of soluble small peptides. The results showed that the enzyme hydrolysis condition was 12% of gluten, pH value of 7.0, neutral protease and alkaline protease added of 3% each, hydrolysis 5 h. Under these conditions, the content of soluble small peptide was 84.34%. The weight average molecular weight of wheat was 764 Da determined by HPLC, and 87.19% of wheat oligopeptide with molecular weight less than 1 000 Da. The results show that the use of feed-grade protease enzyme can significantly increase the content of wheat oligopeptide and reduce the cost, which has the potential to be used as a functional feed additive. [ABSTRACT FROM AUTHOR]

The effects of constant temperature fermentation time on poly-γ-glutamic acid (γ-PGA) production by B. amyloliquefaciens YP-2 was investigated under different temperatures (31 °C, 33 °C, 35 °C, 37 °C and 39 °C). The scheme of step-wise temperature control (0 ~ 4 h, 35 °C ; 4 ~ 7 h, 31 °C ; 7 ~ 10 h, 33 °C ;10 ~ 26 h, 37 °C ;26 ~ 60 h, 31 °C) was formulated following the kinetic analysis of γ-PGA fermentation. Under the variable temperature fermentation condition, the maximum cell productivity and γ-PGA yield reached 1.66 g/(L ⋅ h) 1 and 29.50 g/L, respectively, which was 4.4% and 11.8% higher than those in optimal constant temperature at 37 °C. The results indicated the variable temperature fermentation effectively improved the γ-PGA production by B. amyloliquefaciens YP-2 comparing with constant temperature fermentation. [ABSTRACT FROM AUTHOR]

Based on the data from drilling, core samples, etc., taking the Lower Cambrian Qiongzhusi Formation and the Lower Silurian Longmaxi Formation shales as study target area, authors investigated the accumulation conditions of marine shale gas from the Lower Paleozoic in the south region of Sichuan Basin. The results indicate that the Qiongzhusi Formation and the Longmaxi Formation black shales in this region are mainly formed in shelf sedimentary facies. The study region features great organic-rich shale thickness, high organic abundance (average TOC >2%), Type I and II organic matter, high-over thermal evolution level, rich in brittle mineral, abundant in micro- and nanometer pores, and high gas content, which are in favor of the generation and enrichment of shale gas. Compared with the shales in North America, in which the shale gas has been explored and developed successfully, it is suggested that the Lower Paleozoic in the south region of Sichuan Basin has good accumulation conditions for shale gas. Therefore, the Qiongzhusi and Longmaxi Formations are considered as the practical targets for shale gas exploration, and their favourable areas of shale gas enrichment are also purposed. [ABSTRACT FROM AUTHOR]