Biotechnology Department, AINIA, Parque Tecnológico de Valencia, Av/ Benjamín Franklin 5-11, 46980, Paterna, Valencia, Spain.
R&D Department, Bionet Engineering, Av/ Azul, Parque Tecnológico Fuente Álamo, El Estrecho-Lobosillo, 30320, Fuente Álamo, Murcia, Spain.
Chemosphere. 2022 Jan;287(Pt 4):132401. doi: 10.1016/j.chemosphere.2021.132401. Epub 2021 Sep 30.
The progressive increase of slaughterhouse waste production requires actions for both addressing an environmental issue and creating additional value within a biorefinery concept. In this regard, some of these animal by-products exhibit a significant content of fatty acids that could be efficiently converted into bioplastics such as polyhydroxyalkanoates (PHAs) by adequately performing substrate screening with producing bacterial strains and applying affordable pretreatments. One of the main challenges also relies on the difficulty to emulsify these fat-rich substrates within culture broth and make the fatty acids accessible for the producing bacteria. In this work, the potential of two fat-rich animal by-products, grease trap waste (GTW) and tallow-based jelly (TBJ), as inexpensive carbon sources for microbial growth and PHA production was evaluated for the first time. Upon substrate screening, using different pseudomonadal strains (P. resinovorans, P. putida GPo1, P. putida KT2440) and pretreatment conditions (autoclave-based, thermally-treated or saponified substrates), the highest growth and mcl-PHA production performance was obtained for P. resinovorans, thus producing up to 47% w/w mcl-PHA simply using hygienized GTW. The novel bioprocess described in this study was successfully scaled up to 5 and 15 L, resulting in CDW concentrations of 5.9-12.8 g L, mcl-PHA contents of 33-62% w/w and PHA yields of 0.1-0.4 gPHA g, greatly depending on the substrate dosing strategy used and depending on culture conditions. Moreover, process robustness was confirmed along Test Series by the roughly stable monomeric composition of the biopolymer produced, mainly formed by 3-hydroxyoctanoate and 3-hydroxydecanoate. The research here conducted is crucial for the cost-effectiveness of mcl-PHA production along this new slaughterhouse waste-based biorefinery concept.
屠宰场废物产量的不断增加要求采取行动解决环境问题，并在生物炼制概念中创造额外价值。在这方面，这些动物副产品中的一些含有大量脂肪酸，可以通过对生产菌株进行适当的底物筛选，并采用经济实惠的预处理方法，将其有效地转化为生物塑料，如聚羟基烷酸酯（PHA）。其中一个主要挑战还在于如何将这些富含脂肪的底物乳化到培养液中，并使脂肪酸能够被生产细菌利用。在这项工作中，首次评估了两种富含脂肪的动物副产品，即油脂截留废物（GTW）和牛脂基果冻（TBJ），作为微生物生长和 PHA 生产的廉价碳源的潜力。通过对底物进行筛选，使用不同的假单胞菌菌株（P. resinovorans、P. putida GPo1、P. putida KT2440）和预处理条件（基于高压灭菌器的、热处理的或皂化的底物），发现 P. resinovorans 的生长和 mcl-PHA 生产性能最高，因此仅使用消毒的 GTW 就可生产高达 47%w/w 的 mcl-PHA。本研究中描述的新型生物工艺成功放大到 5 和 15 L，最终 CDW 浓度分别为 5.9-12.8 g/L、mcl-PHA 含量为 33-62%w/w 和 PHA 产率为 0.1-0.4 gPHA/g，这主要取决于所使用的底物投加策略和培养条件。此外，通过测试系列确认了工艺的稳健性，所生产的生物聚合物的单体组成大致稳定，主要由 3-羟基辛酸和 3-羟基癸酸组成。本研究对于基于这种新的屠宰场废物生物炼制概念的 mcl-PHA 生产的成本效益至关重要。
