Characterisation and immunomodulating activities of exo-polysaccharides from submerged cultivation of Hypsizigus marmoreus.

Exo-polysaccharides were purified and characterized from the fermentation broth of Hypsizigus marmoreus, a popular edible mushroom consumed in Asia. Among them, B-I-I and B-II-I exhibited potent complement fixating activity, meanwhile, B-N-I, B-I-I, B-II-I and B-II-II exhibited significant macrophage stimulating activity. Molecular weights of the four exo-polysaccharides were determined to be 6.

Chitinase from a novel strain of Serratia marcescens JPP1 for biocontrol of aflatoxin: molecular characterization and production optimization using response surface methodology.

Chitinase is one of the most important mycolytic enzymes with industrial significance, and produced by a number of organisms. A chitinase producing isolate Serratia marcescens JPP1 was obtained from peanut hulls in Jiangsu Province, China, and exhibited antagonistic activity against aflatoxins. In this study, we describe the optimization of medium composition with increased production of chitinase for the selected bacteria using statistical methods: Plackett-Burman design was applied to find the key ingredients, and central composite design of response surface methodology was used to optimize the levels of key ingredients for the best yield of chitinase.

Efficient purification of antiproliferative polysaccharides from Hypsizigus marmoreus with radial flow chromatography.

The increasing commercial significance of natural polysaccharides for use in medicinal products is stimulating the development of efficient and easy scale-up techniques for polysaccharide purification. In this research, the crude polysaccharides from submerged cultivation broth of Hypsizigus marmoreus were purified using radial flow chromatography (RFC), and the antiproliferative activity of the purified fractions was evaluated in vitro. DEAE Sepharose CL-6B was selected to be packed in the RFC column based on its good resolution, physical stability, and low cost.

Potential of chitinolytic Serratia marcescens strain JPP1 for biological control of Aspergillus parasiticus and aflatoxin.

Serratia marcescens strain JPP1 was isolated from peanut hulls in Huai'an city, Jiangsu Province, China. Its potential to inhibit the mycelial growth of Aspergillus parasiticus and the subsequent aflatoxin production was evaluated. The strain JPP1 could produce chitinase to degrade fungal cell walls, which was the main mechanism of strain JPP1 for biocontrol.

Diversity of culturable root-associated/endophytic bacteria and their chitinolytic and aflatoxin inhibition activity of peanut plant in China.

A total of 72 isolates of root-associated/endophytic (RAE) bacteria were isolated from peanut plants grown in the main producing areas of 6 provinces in China. The 16S rRNA gene sequences of these isolates were determined and phylogenetic analyses revealed that 72 isolates belonged to the classes Bacilli (49 isolates) and Gammaproteobacteria (23 isolates). The majority of RAE bacteria in Bacilli belonged to 2 genera, Bacillus and Lysinibacillus (48 and 1) while those in Gammaproteobacteria belonged to the genera Enterobacter, Serratia, Stenotrophomonas, and Pseudomonas (7, 11, 3 and 2 isolates, respectively).

Cyclo(L-leucyl-L-prolyl) produced by Achromobacter xylosoxidans inhibits aflatoxin production by Aspergillus parasiticus.

Aflatoxins are potent carcinogenic and toxic substances that are produced primarily by Aspergillus flavus and Aspergillus parasiticus. We found that a bacterium remarkably inhibited production of norsolorinic acid, a precursor of aflatoxin, by A. parasiticus.