Characterization of β-1,4-D-mannanase Produced by Bacillus subtilis MSJ-5

Properties of enzyme production of a Bacillus subtitles strain （ MSJ-5 ） isolated from soil were studied in the test. Enzyme production reached the peak when MSJ-5 being cultured in fermentation medium for 32 h. 6-1,4-D-mannanase was the main component of crude enzyme solution, test results showed that the optimal reaction temperature of the enzyme was 50 ℃, the optimum reaction pH was 7.0, and the enzyme was stable when pH was 5.0 -7.0. Hydrolysis test re- suits showed that β-1,4-D-mannanase produced by MSJ-5 had significant viscosity reduction effects on Konjak mannan, and the major hydrolysis product was man- nan oligosaecharide. The results indicated that 6-1,4-D-mannanase produced by B. subtilis MSJ-5 had application potential in feed ingredients and functional oligo- saccharides industry.

青霉MGC07产1,5-α-L-阿拉伯聚糖酶的调控研究

阿拉伯聚糖的酶解产物L-阿拉伯糖、阿魏酰阿拉伯寡糖、阿拉伯寡糖功能独特,但目前对阿拉伯聚糖水解酶的研究较少,尚未开发出具有商业应用潜力的阿拉伯聚糖酶。该研究从土壤中筛选出一株产1,5-α-L-阿拉伯聚糖酶的真菌,结合产孢结构观察和分子生物学鉴定,确定为一株青霉(Penicillium sp.),命名为Penicillium sp.MGC 07。采用单因素法和响应面法优化该菌发酵产酶的条件,结果表明,该菌在甜菜粕39 g/L、磷酸氢二铵16 g/L、初始pH7、培养温度21℃调控条件下,发酵6 d时达到1,5-α-L-阿拉伯聚糖酶活力高峰,酶活为4.3 U/mL,是优化前的3倍。该菌株较优良的产酶能力可为该酶以酶法制备阿拉伯寡糖和阿魏酰阿拉伯寡糖提供理论支持。

β-1,2-Mannan-based glycoconjugates as potential antifungal vaccines

Phosphorylated di-,tri-and tetra-saccharides ofβ-1,2-mannan antigen derived from Candida albicans(C.albicans)cell wall were synthesized and covalently conjugated with keyhole limpet hemocyanin(KLH)and human serum albumin(HSA)via a bifunctional linker under mild conditions.The semi-syntheticβ-1,2-mannoside–KLH conjugates were evaluated for the immunization of BALB/c mice.The ELISA results revealed that all three conjugates could elicit high levels of specific IgG antibodies and the acquired antisera could effectively identify theβ-1,2-mannan epitope.Furthermore,the immunofluorescence and flow cytometry assays also uncovered that the induced antibodies,especially that obtained from immunization withβ-1,2-mannotriose–KLH conjugate(1b),could bind well to fungi cell.Eventually,the structure–immunogenicity relationship analysis ofβ-mannan showed that the length of oligo-β-mannoses had a big impact on their immunogenicity andβ-1,2-mannotriose showed the strongest immunogenicity.The results suggested the great potential ofβ-1,2-mannotriose–KLH conjugate as an antifungal vaccine candidate.

甜菜粕生产果胶低聚糖的研究概况

甜菜粕中含有15%-25%的果胶多糖,果胶低聚糖(POS)是一种新型的益生元,用甜菜粕生产益生元是一种新的、经济可行的方法,但我国尚未开展此研究。本文介绍了甜菜果胶及其低聚糖特性、甜菜果胶低聚糖制备方法,果胶低聚糖的功能活性:促双歧杆菌生长特性、抗癌活性和抗氧化活性等研究进展,并分析了果胶低聚糖益生元的市场前景,展望了甜菜果胶低聚糖的未来发展。对我国甜菜粕副产品开发高附加值产品具有借鉴和参考价值。