Coats Erik R, Loge Frank J, Wolcott Michael P, Englund Karl, McDonald Armando G
Department of Civil Engineering, University of Idaho, Moscow, Idaho, USA.
Water Environ Res. 2007 Nov;79(12):2396-403. doi: 10.2175/106143007x183907.
Biologically derived polyesters known as polyhydroxyalkanoates (PHAs) represent a potentially "sustainable" replacement to fossil-fuel-based thermoplastics. However, current commercial practices that produce PHA with pure microbial cultures grown on renewable, but refined, feedstocks (i.e., glucose) under sterile conditions do not represent a sustainable commodity. Here, we report on PHA production with a mixed microbial consortium indigenous to an activated sludge process on carbon present in municipal wastewaters. Reactors operated under anaerobic/aerobic and aerobic-only mode and fed primary solids fermenter liquor maintained a mixed microbial consortium capable of synthesizing PHA at 10 to 25% (w/w), while reducing soluble COD by approximately 62 to 71%. More critically, an aerobic batch reactor seeded from the anaerobic/aerobic reactor and fed fermenter liquor achieved approximately 53% PHA (w/w). Results presented suggest that environmentally benign production of biodegradable polymers is feasible. We further used PHA-rich biomass to produce a natural fiber-reinforced thermoplastic composite that can be used to offset advanced wastewater treatment costs.
被称为聚羟基脂肪酸酯（PHA）的生物衍生聚酯代表了一种对基于化石燃料的热塑性塑料潜在的“可持续”替代品。然而，目前在无菌条件下，利用在可再生但经过提纯的原料（即葡萄糖）上生长的纯微生物培养物生产PHA的商业做法并不代表一种可持续的商品。在此，我们报告了利用活性污泥法中本地的混合微生物群落，以城市废水中存在的碳为原料生产PHA的情况。在厌氧/好氧和仅好氧模式下运行的反应器，并以初级固体发酵罐液为进料，维持了一个能够合成10%至25%（重量/重量）PHA的混合微生物群落，同时将可溶性化学需氧量降低了约62%至71%。更关键的是，一个从厌氧/好氧反应器接种并以发酵罐液为进料的好氧间歇反应器实现了约53%（重量/重量）的PHA产量。所呈现的结果表明，以环境友好方式生产可生物降解聚合物是可行的。我们进一步利用富含PHA的生物质生产了一种天然纤维增强热塑性复合材料，可用于抵消先进废水处理成本。
