N-Doped porous biocarbon materials derived from soya peptone as efficient electrocatalysts for the ORR

A non-noble metal oxygen reduction catalyst was designed and fabricated via a facile carbonization of soya peptone and ZnCl2.

Statistical Optimization of Media Components for Production of Fibrinolytic Alkaline Metalloproteases from Xenorhabdus indica KB-3

Xenorhabdus indica KB-3, a well-known protease producer, was isolated from its entomopathogenic nematode symbiont Steinernema thermophilum. Since medium constituents are critical to the protease production, the chemical components of the selected medium (soya casein digest broth) were optimized by rotatable central composite design (RCCD) using response surface methodology (RSM). The effects of all five chemical components (considered as independent variables), namely tryptone, soya peptone, dextrose, NaCl, and dipotassium phosphate, on protease production (dependent variable) were studied, and it was found that tryptone and dextrose had maximum influence on protease production. The protease production was increased significantly by 66.31% under optimal medium conditions (tryptone—5.71, soya peptone—4.9, dextrose—1.45, NaCl—6.08, and dipotassium phosphate—0.47 in g/L). To best of knowledge, there are no reports on optimization of medium component for protease production by X. indica KB-3 using RSM and their application in fibrinolysis. This study will be useful for industrial processes for production of protease enzyme from X. indica KB-3 for its application in the field of agriculture and medicine.

Plackett-Burman Design for Media Nutrients of Biocontrol Lysinibacillus xylanilyticus BPM1 against Aflatoxin

Aflatoxins (AFs) are a series of highly toxic and carcinogenic secondary metabolites. In order to eliminate AFs contamination, biological control is one of the more promising techniques. In this study, we describe the optimization of media nutrients for the selected biocontrol bacterium, Lysinibacillus xylanilyticus strain BPM1. The strain was isolated from the peanut hulls in Shandong Province, China and exhibited antagonistic activity against aflatoxins. Maltose and sucrose were identified as best carbon source, while soya peptone and yeast extract as nitrogen source led to the highest OD600 observations. Medium composition was optimized using Plackett-Burman design, which was applied to find the key ingredients. The results revealed that the most significant two factors which were more effective in the fermentation of L. xylanilyticus BPM1 were soya peptone and yeast extract.

Screening of Nitrogen Sources in the Medium for Streptococcus thermophilus Using Plackett–Burman Design

This study demonstrates that the type of nitrogen sources has an important influence on the growth of Streptococcus thermophilus.at the same time ,viable counts was studied by in the medium containing various nitrogen sources (peptone, yeast extract, meat extract, tryptone，soya peptone and casein hydrolysate). The results indicated that soya peptone was the most efficient nitrogen source and and the influence of different concentrations of soya peptone on growth was determined. The results indicated that viable bacteria were stimulated by the high soya peptone concentration (30g/L).

Proteiniclasticum ruminis gen. nov., sp. nov., a strictly anaerobic proteolytic bacterium isolated from yak rumen

Two strictly anaerobic, proteolytic bacterial strains, designated strain D3RC-2T and D3RC-3r, were isolated from a cellulose-degrading mixed culture enriched from yak rumen content. The strains were Gram-stain negative and non-spore-forming with cell sizes of 0.5–0.8×0.6–2.0 μm. The temperature range for growth was 24–46 °C (optimum 38–39 °C) and the pH range was between 5.6 and 8.7 (optimum 7.0–7.3). Both strains used soya peptone, tryptone, l-phenylalanine, l-leucine, l-methionine, l-serine, l-valine, l-threonine and l-histidine as carbon and nitrogen sources, but did not use any of the saccharides tested. The major fermentation products from PY medium were acetate, propionate and iso-butyrate. The DNA G+C contents of strains D3RC-2T and D3RC-3r were 41.0±0.1 mol% and 41.3±0.1 mol% (HPLC), respectively. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the two strains represented a new phyletic sublineage within the family Clostridiaceae, with <93.8 % 16S rRNA gene sequence similarity to recognized species. On the basis of the phenotypic, genotypic and physiological evidence, strains D3RC-2T and D3RC-3r are proposed as representing a novel species of a new genus, for which the name Proteiniclasticum ruminis gen. nov., sp. nov. is proposed. The type strain of the type species is D3RC-2T (=AS 1.5057T=JCM 14817T).

Detection of Group D Salmonellae Including Salmonella Enteritidis in Eggs by Polymyxin-Based Enzyme-Linked Immunosorbent Assay

A high-throughput, rapid method was devised for the detection of Salmonella Enteritidis in egg products. For each target organism, preenrichment in nutrient broth was followed by selective enrichment in Rappaport-Vassiliadis soya peptone and tetrathionate brilliant green broths or by plating on modified semisolid Rappaport Vassiliadis (MSRV) agar medium. The presence of Salmonella Enteritidis was determined by subjecting portions of the selective broth cultures or swarming growth on MSRV medium to an enzyme-linked immunosorbent assay (ELISA) procedure using polymyxin immobilized in the wells of a microtiter plate as a high-affinity adsorbent for lipopolysaccharide (LPS) antigens. Sample extracts were reacted with polymyxin-coated microwells, and captured LPS antigens were detected immunoenzymatically with a commercially available Salmonella factor O9–specific antibody. The polymyxin-ELISA was 100% sensitive and 100% specific for Salmonella strains bearing the O9 antigen. When the ELISA was combined with enrichment using either the selective broths or plating on MSRV medium, the system was an effective means for detection of Salmonella Enteritidis in artificially inoculated egg products. The polymyxin-ELISA is a simple and inexpensive assay for group D salmonellae (including Salmonella Enteritidis) in a convenient 96-well microtiter plate format, making this system ideally suited for processing large numbers of samples.

An evaluation of commercially available dehydrated Rappaport-Vassiliadis medium for the isolation of salmonellae from poultry

SUMMARYA total of 745 samples of chicken giblets was cultured to determine the relative efficiency of a commercially available Rappaport-Vassiliadis medium (RV-Oxoid). Experiments to determine the optimum inoculation ratio showed that 1:100 was superior to the other ratios tested. Comparison of RV-Oxoid with standard RV and RV-medium prepared using soya peptone (RV-soya) showed that after 24 h RV-soya was significantly better than RV-Oxoid (P< 0·05), although there was no significant difference between standard RV and RV-Oxoid. Furthermore, when the duration of incubation was extended to 48 h there was no significant difference between the three media (P> 0·25).We conclude that RV-Oxoid is a satisfactory product for the isolation of salmoncllae from poultry, providing that it is inoculated at a ratio of 1:100 and is incubated for 48h. Its use can therefore be recommended to laboratories who wish to use a dehydrated medium.