Elucidating the key environmental parameters during the production of ectoines from biogas by mixed methanotrophic consortia
The 4th DEEP PURPLE Publication was received 29 January 2021, revised 6 July 2021, accepted 31 July 2021, and made available online 5 August 2021 in the ELSEVIER Journal of Environmental Management. The author team (See below in cite and share) is from the Institute of Sustainable Processes, University of Valladolid, Dr. Mergelina s/n., Valladolid, 47011, Spain, which belongs to the Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n., Valladolid, 47011, Spain.
Anaerobic digestion (AD) is a robust biotechnology for the valorisation of organic waste into biogas. However, the rapid decrease in renewable electricity prices requires alternative uses of biogas. In this context, the engineering of innovative platforms for the bio-production of chemicals from CH4 has recently emerged. The extremolyte and osmoprotectant ectoine, with a market price of ~1000€/Kg, is the industrial flagship of CH4-based bio-chemicals. This work aimed at optimizing the accumulation of ectoines using mixed microbial consortia enriched from saline environments (a salt lagoon and a salt river) and activated sludge, and biogas as feedstock. The influence of NaCl (0, 3, 6, 9 and 12 %) and Na2WO4 (0, 35 and 70 μg L−1) concentrations and incubation temperature (15, 25 and 35 °C) on the stoichiometry and kinetics of the methanotrophic consortia was investigated. Consortia enriched from activated sludge at 15 °C accumulated the highest yields of ectoine and hydroxyectoine at 6 % NaCl (105.0 ± 27.2 and 24.2 ± 5.4 mgextremolyte gbiomass−1, respectively). The consortia enriched from the salt lagoon accumulated the highest yield of ectoine and hydroxyectoine at 9 % NaCl (56.6 ± 2.5 and 51.0 ± 2.0 mgextremolyte gbiomass−1, respectively) at 25 °C. The supplementation of tungsten to the cultivation medium did not impact on the accumulation of ectoines in any of the consortia. A molecular characterization of the enrichments revealed a relative abundance of ectoine-accumulating methanotrophs of 7–16 %, with Methylomicrobium buryatense and Methylomicrobium japanense as the main players in the bioconversion of methane into ectoine.
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Alessandro A. Carmona-Martínez, Eva Marcos-Rodrigo, Sergio Bordel, David Marín, Raquel Herrero-Lobo ,Pedro A. García-Encina, Raúl Muñoz, Elucidating the key environmental parameters during the production of ectoines from biogas by mixed methanotrophic consortia, Journal of Environmental Management, Elsevier, Volume 298, 15 November 2021, 113462