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Pacheco Nicolas Orellana-Saez Matias Pepczynska Marzena Enrione Javier Bassas-Galia Monica Borrero-de Acuña Jose M. Zacconi Flavia C. Marcoleta Andrés E. Poblete-Castro Ignacio 《Journal of industrial microbiology & biotechnology》2019,46(8):1139-1153
Journal of Industrial Microbiology & Biotechnology - Extreme environments are a unique source of microorganisms encoding metabolic capacities that remain largely unexplored. In this work, we... 相似文献
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José Manuel Borrero-de Acuña Izabook Gutierrez-Urrutia Cristian Hidalgo-Dumont Carla Aravena-Carrasco Matias Orellana-Saez Nestor Palominos-Gonzalez Jozef B. J. H. van Duuren Viktoria Wagner Lars Gläser Judith Becker Michael Kohlstedt Flavia C. Zacconi Christoph Wittmann Ignacio Poblete-Castro 《Microbial biotechnology》2021,14(6):2385-2402
Lignin-based aromatics are attractive raw materials to derive medium-chain length poly(3-hydroxyalkanoates) (mcl-PHAs), biodegradable polymers of commercial value. So far, this conversion has exclusively used the ortho-cleavage route of Pseudomonas putida KT2440, which results in the secretion of toxic intermediates and limited performance. Pseudomonas putida H exhibits the ortho- and the meta-cleavage pathways where the latter appears promising because it stoichiometrically yields higher levels of acetyl-CoA. Here, we created a double-mutant H-ΔcatAΔA2 that utilizes the meta route exclusively and synthesized 30% more PHA on benzoate than the parental strain but suffered from catechol accumulation. The single deletion of the catA2 gene in the H strain provoked a slight attenuation on the enzymatic capacity of the ortho route (25%) and activation of the meta route by nearly 8-fold, producing twice as much mcl-PHAs compared to the wild type. Inline, the mutant H-ΔcatA2 showed a 2-fold increase in the intracellular malonyl-CoA abundance – the main precursor for mcl-PHAs synthesis. As inferred from flux simulation and enzyme activity assays, the superior performance of H-ΔcatA2 benefited from reduced flux through the TCA cycle and malic enzyme and diminished by-product formation. In a benzoate-based fed-batch, P. putida H-ΔcatA2 achieved a PHA titre of 6.1 g l–1 and a volumetric productivity of 1.8 g l–1 day–1. Using Kraft lignin hydrolysate as feedstock, the engineered strain formed 1.4 g l- 1 PHA. The balancing of carbon flux between the parallel catechol-degrading routes emerges as an important strategy to prevent intermediate accumulation and elevate mcl-PHA production in P. putida H and, as shown here, sets the next level to derive this sustainable biopolymer from lignin hydrolysates and aromatics. 相似文献
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