Scion, Te Papa Tipu Innovation Park, 49 Sala Street, Private Bag 3020, Rotorua, 3046, New Zealand.
Scion, Te Papa Tipu Innovation Park, 49 Sala Street, Private Bag 3020, Rotorua, 3046, New Zealand; GNS Science, Wairakei Research Centre, 114 Karetoto Road, Wairakei, Taupō, 3352, New Zealand.
Water Res. 2018 Sep 1;140:1-11. doi: 10.1016/j.watres.2018.04.017. Epub 2018 Apr 12.
Organic waste residues can be hydrothermally treated to produce organic acid rich liquors. These hydrothermal liquors are a potential feedstock for polyhydroxyalkanoate (PHA) production. We investigated the effect of dissolved oxygen concentration and substrate feeding regimes on PHA accumulation and yield using two hydrothermal liquors derived from a mixture of primary and secondary municipal wastewater treatment sludge and food waste. The enriched culture accumulated a maximum of 41% PHA of cell dry weight within 7 h; which is among the highest reported for N and P rich hydrothermal liquors. Recovered PHA was 77% polyhydroxybutyrate and 23% polyhydroxyvalerate by mass. The families Rhodocyclaceae (84%) and Saprospiraceae (20.5%) were the dominant Proteobacteria (73%) in the enriched culture. The third most abundant bacterial genus, Bdellovibrio, includes species of known predators of PHA producers which may lead to suboptimal PHA accumulation. The PHA yield was directly proportional to DO concentration for ammonia stripped liquor (ASL) and inversely proportional to DO concentration for low strength liquor (LSL). The highest yield of 0.50 Cmol PHA/Cmol substrate was obtained for ASL at 25% DO saturation. A progressively increasing substrate feeding regime resulted in increased PHA yields. These findings demonstrate that substrate feeding regime and oxygen concentration can be used to control the PHA yield and accumulation rate thereby enhancing PHA production viability from nutrient rich biomass streams.
有机废物残渣可以通过水热法处理生成富含有机酸的液体。这些水热液体是生产聚羟基烷酸酯（PHA）的潜在原料。我们研究了溶解氧浓度和底物进料方式对两种水热液体中PHA 积累和产率的影响，这两种水热液体来源于市政一级和二级污水处理厂污泥与食物垃圾的混合物。富集培养物在 7 小时内积累了高达 41%的细胞干重 PHA，这在富氮和富磷的水热液体中属于较高水平。回收的 PHA 中，按质量计 77%为聚羟基丁酸酯，23%为聚羟基戊酸酯。在富集培养物中，优势变形菌门（Proteobacteria）的菌属为红环菌科（Rhodocyclaceae，84%）和螺旋菌科（Saprospiraceae，20.5%）。第三丰富的细菌属为蛭弧菌属（Bdellovibrio），其中包含已知的 PHA 产生菌的捕食者，这可能导致 PHA 积累不理想。对于氨汽提液（ammonia stripped liquor，ASL），PHA 产率与 DO 浓度成正比，而对于低强度液（low strength liquor，LSL），PHA 产率与 DO 浓度成反比。在 25% DO 饱和度时，ASL 的最高 PHA 产率为 0.50 Cmol PHA/Cmol 底物。采用逐渐增加的底物进料方式，PHA 产率会增加。这些发现表明，可以通过控制底物进料方式和氧气浓度来控制 PHA 的产率和积累速率，从而提高从富营养生物质流生产 PHA 的可行性。
