Department of Environment and Forest Biology, SUNY-College of Environmental Science and Forestry, Syracuse, NY 13210, USA.
J Ind Microbiol Biotechnol. 2012 Mar;39(3):459-69. doi: 10.1007/s10295-011-1040-6. Epub 2011 Sep 28.
Sugar maple hemicellulosic hydrolysate containing 71.9 g/l of xylose was used as an inexpensive feedstock to produce polyhydroxyalkanoates (PHAs) by Burkholderia cepacia ATCC 17759. Several inhibitory compounds present in wood hydrolysate were analyzed for effects on cell growth and PHA production with strong inhibition observed at concentrations of 1 g/l furfural, 2 g/l vanillin, 7 g/l levulinic acid, and 1 M acetic acid. Gradual catabolism of lower concentrations of these inhibitors was observed in this study. To increase the fermentability of wood hydrolysate, several detoxification methods were tested. Overliming combined with low-temperature sterilization resulted in the highest removal of total inhibitory phenolics (65%). A fed-batch fermentation exhibited maximum PHA production after 96 h (8.72 g PHA/L broth and 51.4% of dry cell weight). Compositional analysis by NMR and physical-chemical characterization showed that PHA produced from wood hydrolysate was composed of polyhydroxybutyrate (PHB) with a molecular mass (M (N)) of 450.8 kDa, a melting temperature (T (m)) of 174.4°C, a glass transition temperature (T (g)) of 7.31°C, and a decomposition temperature (T (decomp)) of 268.6°C.
以糖枫半纤维素水解液（含 71.9 g/L 木糖）为廉价原料，利用洋葱伯克霍尔德氏菌 ATCC 17759 生产聚羟基烷酸酯（PHA）。分析了木质水解液中几种存在的抑制性化合物对细胞生长和 PHA 生产的影响，在 1 g/L 糠醛、2 g/L 香草醛、7 g/L 乙酰丙酸和 1 M 乙酸的浓度下观察到强烈的抑制作用。在本研究中观察到这些抑制剂的低浓度逐渐代谢。为了提高木质水解液的可发酵性，测试了几种解毒方法。过石灰处理结合低温灭菌可去除总抑制性酚类（65%）。分批补料发酵在 96 h 后达到最大 PHA 产量（8.72 g PHA/L 发酵液和 51.4%的干细胞重量）。NMR 组成分析和物理化学特性表明，从木质水解液中生产的 PHA 由聚羟基丁酸酯（PHB）组成，分子量（M（N））为 450.8 kDa，熔点（T（m））为 174.4°C，玻璃化转变温度（T（g））为 7.31°C，分解温度（T（decomp））为 268.6°C。
