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2021-06-04T12:01:56Z urn:hdl:10324/46751 Elucidating the influence of environmental factors on biogas-based polyhydroxybutyrate production by Methylocystis hirsuta CSC1 Rodríguez Muñoz, Yadira Firmino, Paulo Igor Milen Arnáiz, Esther Lebrero Fernández, Raquel Muñoz Torre, Raúl Producción Científica The valorization of biogas as a feedstock for the generation of added-value bioproducts will play a key role on the sustainability of anaerobic digestion. The present work assessed the influence of key environmental parameters (O2:CH4 ratio, temperature and nitrogen source) on the growth and polyhydroxybutyrate (PHB) synthesis under nitrogen limiting conditions of the type II methanotroph Methylocystis hirsuta CSC1 using biogas as a feedstock. The O2:CH4 ratios tested (1:1, 1.5:1 and 2:1) did not affect significantly M. hirsuta CSC1 growth yields (~5 g TSS mol−1 CH4), although lower CH4 removal rates were reached under O2-limiting conditions (ratio 1:1). The highest PHB content (45 wt%) was achieved at a ratio 2:1 and was threefold higher than those obtained at lower ratios (~15 wt%). The increase in temperature from 15 to 25 °C resulted in increases in the growth yield (from 5 to 6 g TSS mol−1 CH4) and PHB content (from 32 to 40 wt%). Conversely, the lowest PHB content (30 wt%) was reached at 37 °C, together with a negligible growth under nutrient sufficient conditions. The nitrogen source also played a key role on both M. hirsuta CSC1 growth and PHB synthesis. Thus, ammonium resulted in the highest growth yield (7 g TSS mol−1 CH4), although the maximum PHB content was achieved when biomass was previously grown in nitrate as the nitrogen source (41 wt%). Nitrite exerted an inhibitory effect on M. hirsuta CSC1 growth. 2021-06-04T12:01:56Z 2021-06-04T12:01:56Z 2020 info:eu-repo/semantics/article Science of The Total Environment, 2020, vol. 706, n. 1, p. 135136 0048-9697 https://uvadoc.uva.es/handle/10324/46751 10.1016/j.scitotenv.2019.135136 135136 Science of The Total Environment 706 eng https://www.sciencedirect.com/science/article/abs/pii/S0048969719351289 info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-nd/4.0/ © 2020 Elsevier Attribution-NonCommercial-NoDerivatives 4.0 Internacional Elsevier