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oai:uvadoc.uva.es:10324/301042025-03-26T19:10:03Zcom_10324_1173com_10324_931com_10324_894com_10324_31059com_10324_954col_10324_1371col_10324_31061

Simultaneous methane abatement and PHB production by Methylocystis hirsuta in a novel gas-recycling bubble column bioreactor García Pérez, Teresa López Alonso, Juan Carlos Passos, Fabiana Lebrero Fernández, Raquel Revah, Sergio Muñoz Torre, Raúl Producción Científica The limited gas–liquid mass transfer represents the main challenge in the operation of cost-effective bioreactors devoted to the treatment of poorly soluble gas pollutants such as methane (CH4). This study evaluates the influence of internal gas-recycling strategies on the enhancement of CH4 abatement in a bubble column bioreactor inoculated with the methanotroph Methylocystis hirsuta. Maximum CH4 removal efficiencies of 72.9 ± 0.5% (corresponding to elimination capacities of 35.2 ± 0.4 g m−3 h−1) were recorded under process operation at an empty bed residence time of 30 min and 0.50 m3gas m−3reactor min−1 of internal gas-recycling rate. The accumulation of poly-3-hydroxybutyrate (PHB) in M. hirsuta was evaluated batchwise under limitations of potassium, manganese, nitrogen, and nitrogen with excess of iron. Nitrogen starvation resulted in the highest PHB content (28 ± 1%). Likewise, the implementation of sequential N starvation cycles in a continuous bubble column reactor operated at a gas residence time of 30 min and an internal gas-recycling rate of 0.50 m3gas m−3reactor min−1 supported a PHB content of up to 34.6 ± 2.5%, with a volumetric PHB productivity of 1.4 ± 0.4 kg m−3 d−1 and elimination capacities of 16.2 ± 9.5 g m−3 h−1. 2018-06-13T12:54:13Z 2018 info:eu-repo/semantics/article Chemical Engineering Journal, Volume 334, 2018, Pages 691-697 1385-8947 http://uvadoc.uva.es/handle/10324/30104 10.1016/j.cej.2017.10.106 eng https://www.sciencedirect.com/science/article/pii/S1385894717318211 info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-nd/4.0/ Attribution-NonCommercial-NoDerivatives 4.0 International Elsevier SI