Butyrogenic effect of galactosyl and mannosyl carbohydrates and their regulation on piglet intestinal microbiota.

Diarrhea is a global problem that causes economic losses in the pig industry. There is a growing attention on finding new alternatives to antibiotics to solve this problem. Hence, this study aimed to compare the prebiotic activity of low-molecular-weight hydrolyzed guar gum (GMPS) with commercial manno-oligosaccharide (MOS) and galacto-oligosaccharide (GOS). We further identified their combined effects along with probiotic Clostridium butyricum on regulating the intestinal microbiota of diarrheal piglet by in vitro fermentation. All the tested non-digestible carbohydrates (NDCs) showed favorable short-chain fatty acid-producing activity, and GOS and GMPS showed the highest production of lactate and butyrate, respectively. After 48 h of fermentation, the greatest enhancement in the abundance of Clostridium sensu stricto 1 was observed with the combination of GMPS and C. butyricum. Notably, all the selected NDCs significantly decreased the abundances of pathogenic bacteria genera Escherichia-Shigella and Fusobacterium and reduced the production of potentially toxic metabolites, including ammonia nitrogen, indole, and skatole. These findings demonstrated that by associating with the chemical structure, GMPS exhibited butyrogenic effects in stimulating the proliferation of C. butyricum. Thus, our results provided a theoretical foundation for further application of galactosyl and mannosyl NDCs in the livestock industry. KEY POINTS: • Galactosyl and mannosyl NDCs showed selective prebiotic effects. • GMPS, GOS, and MOS reduced pathogenic bacteria and toxic metabolites production. • GMPS specifically enhanced the Clostridium sensu stricto 1 and butyrate production.

Expression, Purification and Characterization of Chondroitinase AC II from Marine Bacterium Arthrobacter sp. CS01.

Chondroitinase (ChSase), a type of glycosaminoglycan (GAG) lyase, can degrade chondroitin sulfate (CS) to unsaturate oligosaccharides, with various functional activities. In this study, ChSase AC II from a newly isolated marine bacterium Arthrobacter sp. CS01 was cloned, expressed in Pichia pastoris X33, purified, and characterized. ChSase AC II, with a molecular weight of approximately 100 kDa and a specific activity of 18.7 U/mg, showed the highest activity at 37 °C and pH 6.5 and maintained stability at a broad range of pH (5⁻7.5) and temperature (below 35 °C). The enzyme activity was increased in the presence of Mn2+ and was strongly inhibited by Hg2+. Moreover, the kinetic parameters of ChSase AC II against CS-A, CS-C, and HA were determined. TLC and ESI-MS analysis of the degradation products indicated that ChSase AC II displayed an exolytic action mode and completely hydrolyzed three substrates into oligosaccharides with low degrees of polymerization (DPs). All these features make ChSase AC II a promising candidate for the full use of GAG to produce oligosaccharides.

Expression, purification and characterisation of chondroitinase AC II with glyceraldehyde-3-phosphate dehydrogenase tag and chaperone (GroEs-GroEL) from Arthrobacter sp. CS01.

In this study, chondroitinase (ChSase) AC II from Arthrobacter sp. CS01 was cloned, expressed in Escherichia coli BL21 (DE3), purified and characterised. To assist in protein folding and improve on high protein aggregation rates, two strategies involving chaperones and fusion tags were chosen to increase enzyme activity and improve enzymatic properties. ChSase AC II enzyme activity increased from 3.12 to 9.15 U/ml with chaperone GroEs-GroEL, and the specific activity increased from 19.8 to 25.74 U/mg with the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) tag. ChSase AC II and GAPDH-ChSase AC II displayed maximum activities at 37 °C and 40 °C, at pH 6.5 and 7.0, respectively. GAPDH-ChSase AC II activity remained above 69.8% after incubation at 40 °C for 120 min, and ChSase AC II activity remained approximately 32.1% under the same conditions, indicating that ChSase AC II thermostability was enhanced by the GAPDH tag. These properties suggested that the enzymes are promising prospects in medical and industrial applications.