Pulp and paper factories produce several residues that can be explored and valorized through polyhydroxyalkanoate (PHA) production via a three-step process. The objective of this work was focused on the selection step. Acidified hardwood spent sulfite liquor (HSSL), a fermented waste stream from a pulp and paper factory, was used to select a mixed microbial culture (MMC) in a sequencing batch reactor (SBR) operated for 156 days under different operational conditions. The MMC adapted to the imposed conditions, revealing its robustness whenever the operational parameters were changed. Feast-to-Famine ratio was kept below or equal to 0.2, with constant production of a copolymer of P(3HB-co-3 HV), and with storage contents values over 30%. Changes in the operational conditions, namely cycle length, and organic load rate (OLR), successfully led to the selection of an MMC with a stable accumulation capacity and an increased biomass concentration. Next Generation Sequencing analysis was performed on samples collected during the SBR operational period. The analysis of the microbial composition of the MMC showed a rise in PHA-accumulating bacteria over time. Acidovorax and Comamonas species were found mainly to drive the PHA storage process during the first two periods of operation. After an increase in the OLR, in the last period, a shift towards Comamonas dominance occurred, suggesting a higher tolerance to the inhibitory compounds of the HSSL for this genus.

中文翻译：

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使用发酵阔叶木废亚硫酸盐液富集 PHA 储存微生物的混合微生物培养物

纸浆和造纸厂会产生多种残留物，这些残留物可以通过三步过程通过聚羟基链烷酸酯 (PHA) 生产进行探索和评估。这项工作的目标集中在选择步骤上。酸化硬木亚硫酸盐废液 (HSSL)，一种来自纸浆和造纸厂的发酵废物流，用于在不同操作条件下运行 156 天的序批式反应器 (SBR) 中选择混合微生物培养物 (MMC)。MMC 适应了强加的条件，无论何时更改操作参数，都显示出其稳健性。盛宴与饥荒之比保持在 0.2 以下或等于 0.2，持续生产 P(3HB-co-3 HV) 共聚物，储存含量值超过 30%。操作条件的变化，即周期长度和有机负荷率 (OLR)，成功地导致选择了具有稳定积累能力和增加的生物量浓度的 MMC。对 SBR 运行期间收集的样品进行了下一代测序分析。MMC 微生物组成的分析表明，随着时间的推移，积累 PHA 的细菌会增加。发现酸食和毛单胞菌物种主要在前两个操作期间推动 PHA 存储过程。在 OLR 增加后，在最后一个时期，发生了向毛单胞菌优势转变，表明该属对 HSSL 的抑制性化合物具有更高的耐受性。MMC 微生物组成的分析表明，随着时间的推移，积累 PHA 的细菌会增加。发现酸食和毛单胞菌物种主要在前两个操作期间推动 PHA 存储过程。在 OLR 增加后，在最后一个时期，发生了向毛单胞菌优势转变，表明该属对 HSSL 的抑制性化合物具有更高的耐受性。MMC 微生物组成的分析表明，随着时间的推移，积累 PHA 的细菌会增加。发现酸食和毛单胞菌物种主要在前两个操作期间推动 PHA 存储过程。在 OLR 增加后，在最后一个时期，发生了向毛单胞菌优势转变，表明该属对 HSSL 的抑制性化合物具有更高的耐受性。