The bone-degrading enzyme machinery: From multi-component understanding to the treatment of residues from the meat industry.

Many microorganisms feed on the tissue and recalcitrant bone materials from dead animals, however little is known about the collaborative effort and characteristics of their enzymes. In this study, microbial metagenomes from symbionts of the marine bone-dwelling worm Osedax mucofloris, and from microbial biofilms growing on experimentally deployed bone surfaces were screened for specialized bone-degrading enzymes. A total of 2,043 taxonomically (closest match within 40 phyla) and functionally (1 proteolytic and 9 glycohydrolytic activities) diverse and non-redundant sequences (median pairwise identity of 23.6%) encoding such enzymes were retrieved. The taxonomic assignation and the median identity of 72.2% to homologous proteins reflect microbial and functional novelty associated to a specialized bone-degrading marine community. Binning suggests that only one generalist hosting all ten targeted activities, working in synergy with multiple specialists hosting a few or individual activities. Collagenases were the most abundant enzyme class, representing 48% of the total hits. A total of 47 diverse enzymes, representing 8 hydrolytic activities, were produced in Escherichia coli, whereof 13 were soluble and active. The biochemical analyses revealed a wide range of optimal pH (4.0-7.0), optimal temperature (5-65 °C), and of accepted substrates, specific to each microbial enzyme. This versatility may contribute to a high environmental plasticity of bone-degrading marine consortia that can be confronted to diverse habitats and bone materials. Through bone-meal degradation tests, we further demonstrated that some of these enzymes, particularly those from Flavobacteriaceae and Marinifilaceae, may be an asset for development of new value chains in the biorefinery industry.

Antihyperglycemic and hypoglycemic activities of the aqueous leaf extract of Rubus Erlangeri Engl (Rosacea) in mice.

BACKGROUND: The prevalence of diabetes mellitus is on the inexorable rise despite the promises of a wide range of conventional medications. Thus, there is a need to scientifically investigate plants for antidiabetic effect. METHODS: After the Rubus Erlanrige Engl (Rosaceae) leaf has been decocted, the plant extract's antidiabetic activity was first investigated in vitro and then in vivo. The in vitro activity was assessed using 3, 5-Dinitrosalicylic acid, and 2,2-diphenyl-1-picrylhydrazine method for α-amylase inhibition and antioxidant effect respectively. On the other hand, the in vivo antidiabetic activity was carried out in normoglycemic, glucose loaded (2.5 g/kg) and single dose streptozotocin (200 mg/kg) induced diabetic mice. RESULTS: Acute toxicity study showed the extract is safe with ≥2 g/kg. The in vitro results demonstrated the extract has an IC50 of 7.34 ± 0.02 and 10.38 ± 0.0.62 µg/ml for antioxidant and α-amylase inhibition activity respectively. On the other hand, the in vivo study revealed that the extract significantly reduced blood glucose level following glucose loading. The extract did not, however, produce a significant reduction of glucose level in normal mice indicating low risk of hypoglycemia. The extract also significantly decreased blood glucose levels in streptozotocin-induced diabetic mice. In the single dose study, the extract lowered blood glucose level all except by lower dose at the 3rd and 4th h (p < 0.05). In repeated dose studies, the reduction in fasting blood glucose was significant with all doses of the extract from the 2nd week onwards. In addition, the extract produced less reduction in body weight after diabetic induction. CONCLUSION: The findings collectively indicate that the extract has an antidiabetic activity, with low risk of hypoglycemia, probably mediated by various secondary metabolites that act in synergy.

Production and characterization of functional wheat bran hydrolysate rich in reducing sugars, xylooligosaccharides and phenolic acids.

The aim was to enhance production of functional hydrolysate from wheat bran (WB). WB was hydrolyzed with 3000 U/mL ɑ-amylase and 1200 U/mL alkaline protease to prepare WB insoluble dietary fibre (WBIDF). Functional hydrolysate production from the extract containing crude xylan of WBIDF by xylanase was optimized by Taguchi method. The optimal condition for xylan degradation and functional substances production was 78.50 U/mL xylanase, pH 10.0, 50 °C, and reaction time 6 h. The maximum yield of reducing sugars was 614.0 µg/mL, xylobiose increased from 12.9 µg/mL to 213.3 µg/mL, xylotriose increased from 34.9 µg/mL to 174.0 µg/mL, ferulic acid 13.1 µg/mL made up 57.5 % of the total identifiable phenolic pool in the hydrolysate. The total antioxidant activity of hydrolysate was 141.8 mg ascorbic acid equivalents g-1 crude xylan, and the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity reached 92.7 %. The hydrolysate exhibited great potential in agricultural and food industry application.