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BSH-1 is an O‑acetyl-arabinoxylan obtained from bamboo shavings. This study investigated its fermentation behavior by human colonic microbiota in vitro. Results showed that BSH-1 remarkably modulated the composition of human colonic microbiota, mainly by increasing the growth of potential beneficial genera (i.e. Bifidobacterium, Lactobacillus, Bacteroides, Prevotella_7, Parabacteroides) and by decreasing the growth of potential harmful genera (i.e. Fusobacterium, Lachnospiraceae_UCG-008, Bilophila and Desulfovibrio). BSH-1 significantly promoted the production of short-chain fatty acids, especially acetic, propionic and n-butyric acids. After 48 h fermentation, the concentration of n-butyric acid in BSH-1 fermentation culture was increased by 2.41 times compared to the blank. During fermentation, the activity of acetyl xylan esterase, arabinofuranosidase, xylanase and xylosidase was enhanced. Moreover, free arabinose, xylose, xylobiose, xylotriose, xylotetraose, xylopentaose and xylohexaose were detected. These results suggest that BSH-1 could potentially be a functional ingredient to improve gut health.

Bacillus subtilis strain SB13 which is isolated in our previous work was confirmed to produce endoglucanase. In this study, a novel endoglucanase gene (accession number: KX576676) was identified and cloned from SB13. Compared with other consensus sequence of reported endoglucanase genes in the GenBank database, this gene displays five differences (including T740C,A874G,A983G, T1210G and T1301C), which leading to five amino acid changes. Homology modeling has indicated that these five changes were located in the α-helix and random coil regions of the glycosyl hydrolase family 5 (GH5) domain, the random coil and β-sandwich of the type 3 carbohydrate-binding module (CBM3) domain, and the random coil domain. Aprokaryotic expression vector pET30a-endoglucanase was constructed and the endoglucanase was induced to express. The expressed endoglucanase was confirmed by liquid chromatography-tandem mass spectrometry (LC-MSMS) and detected via reaction with carboxymethyl cellulose. In order to obtain the highest expression level of endoglucanase, the expression conditions including IPTG concentration, temperature and pH were optimized. The recombinant endoglucanase protein was purified using a Ni-NTA column, and the 6 × His-tag was removed with thrombin. The results showed that both the modified and unmodified purified endoglucanase had high activity (7.65 ± 0.35 U and 15.05 ± 1.81 U, respectively), thus demonstrating the potential use of this enzyme in various industrial applications. The substitutions of L247P,N292D, F404V and L434P might contribute to the activity of the endoglucanase, and the insertion of a 6 × His-tag at the N-terminal of the endoglucanase might also affect its activity.

Objective To screen for and characterize lactic acid bacteria strains with the ability to produce fermented milk and reduce cholesterol levels. Methods The strains were isolated from traditional fermented milk in China. In vitro and in vivo evaluation of cholesterol-reduction were used to identify and verify strains of interest. Characteristics were analyzed using spectrophotometry and plate counting assays. Results The isolate HLX37 consistently produced fermented milk with strong cholesterol-reducing properties was identified as Lactobacillus plantarum (accession number: KR105940) and was thus selected for further study. The cholesterol reduction by strain HLX37 was 45.84%. The isolates were acid-tolerant at pH 2.5 and bile-tolerant at 0.5% (w/v) in simulated gastric juice (pH 2.5) for 2 h and in simulated intestinal fluid (pH 8.0) for 3 h. The auto-aggregation rate increased to 87.74% after 24 h, while the co-aggregation with Escherichia coli DH5 was 27.76%. Strain HLX37 was intrinsically resistant to antibiotics such as penicillin, tobramycin, kanamycin, streptomycin, vancomycin and amikacin. Compared with rats in the model hyperlipidemia group, the total cholesterol content in the serum and the liver as well as the atherogenic index of rats in the viable fermented milk group significantly decreased by 23.33%, 32.37% and 40.23%, respectively. Fewer fat vacuoles and other lesions in liver tissue were present in both the inactivated and viable fermented milk groups compared to the model group. Conclusion These studies indicate that strain HLX37 of L. plantarum demonstrates probiotic potential, potential for use as a candidate for commercial use for promoting health.

BSH, BSH-1 and BSH-2 are three naturally acetylated xylans obtained from bamboo shavings. The study investigated their in vitro digestibility and fermentability by intestinal bacteria. Results showed that BSH, BSH-1 and BSH-2 had low digestibility in simulated gastric and intestinal fluid, as their molecular weight decreased by 26.7%, 24.1% and 26.0%, respectively, after simulated digestion. BSH, BSH-1, BSH-2 and their corresponding digesta (BSH-D, BSH-1-D, BSH-2-D) could be fermented by Bacteroides spp. and Bifidobacterium spp. in different extent. The growth ratio of B.vulgatus and B.ovatus on the aforementioned six polysaccharides to glucose ranged from 20.8–36.3%. The growth ratio of Bi.breve, Bi.adolescentis, Bi.longum, Bi.animalis and Bi.bifidum on the previously cited six polysaccharides to glucose was 12.1%~ 28.4%. The fermentability of BSH-D, BSH-1-D and BSH-2-D was slightly enhanced as compared to their corresponding undigested sample.

In order to control pollution on swine farms, a comprehensive sewage-treating technology was developed, which used solid-liquid separator after anaerobic fermentation. The technology was based on the principle of maximizing the utilization of resources and energy. The practice of swine sewage treatment on Hung Hing large-scale swine farm in Putian city, showed that pollution problem in swine farm could be solved by such a technology. The out-let wastewater indexes for Suspended Solid, Chemical Oxygen Demand, Biochemical Oxygen Demand, Ammonia Nitrogen, Total Phosphoric were reduced by 97.1%, 97.9%, 98.4%, 86.2% and 81.5%, respectively. The system of the developed technology works well with remarkable economic and ecological benefits.