Breeding Of Zinc-enriched Yeast And Evaluation Of The Bioavailability Of Yeast-zinc

Zinc is one of essential trace elements, and extensively exists in organism. Once lack of it, immunity of human and animal will decline and poor-balanced growth maybe follow. Large amounts of research shows that the situation of zinc scarcity in our children becomes severe. Moreover, one third of zinc demand in the feedstuff should be artificially appended. Due to the low absorption and irritant to stomach mucous membrane of inorganic zinc, people become interested in chelate trace element by amino acid or polysaccharide. Nowadays people pay more attention to yeast which contained various nutriments, because it could be inexpensively produced. What's more it could absorb quite a few elements such as selenium, chromium, zinc.Using UV mutation followed with domestication zinc-enriched yeast HB524 was obtained. Then the orthogonal design dependent on the single factor experiment was conducted for the optimization of its cultivation. Finally the evaluation of organic zinc was studied and the bioavailability of yeast-zinc was analyzed by animal experiment. It's assumed that this paper could be a reference for zinc-enriched yeast industry and its production checkup.It illuminates that the capacity of strain HB524 for zinc enrichment varied obviously in different medium, yet the diluted malt takes precedence of others. Compared with stationary stage, zinc appended in exponential phase could enhance zinc uptake obviously. Proper glucose, urea and KH2PO4 could improve zinc uptake disparately, while soybean sprout extract, which could increase biomass, reduces zinc content remarkably. It could be concluded from orthogonal design L₁₈(2¹Ã—3⁷) that a total zinc of 130 mg/L and the utilization rate of 33.3 percent could be achieved in 48 hours in shaking flasks with the condition: 4Bx malt, 25g/L glucose, 1.0g/L urea, 0.5g/L KH₂PO₄, 10% inoculation quantity, 6mmol/L Zn²⁺ appended within 4 hours after inoculation.It could be deduced from leaching of zinc with EDTA and water that more than 95 percent of the yeast zinc could be released gradually, and 50 percent of zinc ought to be organically bounded. Mechanical ball mill was preferable for yeast cells breaking, and more than 90% of the cells could be cracked with 400 r/min for 24 hours. Whereas the...