Enhancement of mycelial growth and polysaccharide production in Ganoderma lucidum (the Chinese medicinal fungus, `Lingzhi') by the addition of ethanol
Methanol, ethanol, 1-propanol and 2-propanol, at 1.5% (v/v), enhanced the growth and polysaccharide production of Ganoderma lucidum. Ethanol was the most effective at 1.5% (v/v) for increasing the biomass production, however, the maximal polysaccharide concentration was produced with 2% (v/v) ethanol in the medium. There was no new polysaccharide component produced by the addition of ethanol.
Polysaccharides extraction from submerged-cultured mycelium of Grifola frondosa
Alkaline (NaOH) hydrolysis and aqueous extraction method were comparatively studied in polysaccharides extraction from mycelia of Grifola frondosa obtained with submerged-culture. The results show that the polysaccharide content and the total extract rate from alkaline extraction method were obviously higher than those from the aqueous extraction method. The conditions of alkaline extraction were further optimized by the orthogonal matrix method, and the results reveal that the optimum extraction conditions were as follows: ratio of alkaline volume to mycelium weight was 15 (mL/g), alkaline concentration was 1.0 mol/L, hydrolysis temperature was 70°C, and hydrolysis time was 1.5 hour. With the optimized condition, the polysaccharide extraction rate reached 11.18 ± 0.37 %. The mycelial polysaccharide obtained with alkaline hydrolysis method was fractionated by the DEAE column chromatography. Four G. frondosa polysaccharide (GFPS) fractions were isolated in the polysaccharide sample with GFPS-1 as the main component.
Microbial flora of frozen tail meat from captive Nile crocodiles (Crocodylus niloticus).
Frozen tail meat samples from nine Nile crocodiles (Crocodylus niloticus) were evaluated for microbial numbers and types. Microbial analyses yielded a mean aerobic plate count (APC, 30 degrees C) of 4.86 log cfu/g, a mean coliform count (TC, 37 degrees C) of 3.77 log cfu/g and a mean faecal coliform count (FC, 44 degrees C) of 3.40 log cfu/g. Salmonella was isolated from three samples, and beta-haemolytic streptococci from two samples. Yersinia, Aeromonas, Staphylococcus aureus and Bacillus cereus were not isolated. Typical bacterial genera recovered included Flavobacterium, Pseudomonas, Acinetobacter, Enterobacter, Moraxella, Micrococcus, Staphylococcus and Streptococcus.