微生物利用食品废物合成聚羟基烷酸酯

为了降低聚羟基烷酸酯(PHAs)的生产成本,以麦芽、豆类、糖果、冰激凌、牛奶、芝麻油和食醋废物为底物,研究了产碱弧菌(Alcaligenes latus)、表皮匍萄球菌(Staphylococcus epidermidis)和活性污泥合成PHAs的工艺可行性和产物的物化性质.结果表明,通过两段式间歇补料发酵.3类微生物利用麦芽废物合成的聚羟基丁酸酯(PHB)产量最大,分别达细胞内含量的70.1%、16.0%和43.3%.A.latus适应食品废物开始细胞生长和PHAs合成的延迟短,在缺氮阶段合成PHB的产量、产率高.微好氧时,从芝麻油提取出的S.epidermidis可以合成分子量超过1×106的PHB.活性污泥可利用豆类废物合成聚羟基丁酸-羟基戊酸酯(PHBV)共聚物,其中羟基戊酸比例(HV%)占21%.多数食品废物适合合成具有不同物化性质的PHAs.PHAs产物的组分及物化性质受微生物种类、底物类型、发酵条件的影响.

Polyhydroxyalkanoates Microbiological Synthesis from Food Wastes

To reduce the production cost of polyhydroxyalkanoates (PHAs), the process feasibility and physicochemical properties of PHAs synthesized by Alcaligenes latus, Staphylococcus epidermidis and activated sludge from malt waste, soy waste, confectionary waste, ice cream waste, milk waste, sesame oil and vinegar waste were analyzed. Results showed that through two-stage fed-batch fermentation, the maximum yield of PHAs accumulated by the three kinds of microorganisms from malt waste was 70.1%, 16.0% and 43.3%, separately. A.latus adapted itself to the food wastes in PHAs synthesis and new cell growth quickly. A.latus had higher PHAs yield and productivity under nitrogen limited condition. Micro-aerobically, S.epidermidis separated from sesame oil could produce polyhydroxybutyrate (PHB) with molecular weight of over 1×10⁶. From soy waste, activated sludge accumulated polyhydroxybutyrate-co-hydroxyvaluate (PHBV) copolymer which had hydroxyvaleryl content (HV%) of 21%. Most food wastes are suitable for synthesizing PHAs with different physicochemical properties. The composition and properties of PHAs are influenced by the character of microorganism, the selection of substrates and optimization of ferment conditions.