Novel haloalkaliphilic methanotrophic bacteria: An attempt for enhancing methane bio-refinery

Abstract

Methane bioconversion into products with a high market value, such as ectoine or hydroxyectoine, can be optimized via isolation of more efficient novel methanotrophic bacteria. The research here presented focused on the enrichment of methanotrophic consortia able to co-produce different ectoines during CH4 biodegradation. Four different enrichments (Cow3, Slu3, Cow6 and Slu6) were carried out in basal media supplemented with 3 and 6 % NaCl, and using methane as the sole carbon and energy source. The highest ectoine accumulation (~20 mg ectoine g biomass-1) was recorded in the two consortia enriched at 6 % NaCl (Cow6 and Slu6). Moreover, hydroxyectoine was detected for the first time using methane as a feedstock in Cow6 and Slu6 (~5 mg g biomass-1). The majority of the haloalkaliphilic bacteria identified by 16S rRNA community profiling in both consortia have not been previously described as methanotrophs. From these enrichments, two novel strains (representing novel species) capable of using methane as the sole carbon and energy source were isolated: Alishewanella sp. strain RM1 and Halomonas sp. strain PGE1. Halomonas sp. strain PGE1 showed higher ectoine yields (70-92 mg ectoine g biomass-1) than those previously described for other methanotrophs under continuous cultivation mode (~37-70 mg ectoine g biomass-1). The results here obtained highlight the potential of isolating novel methanotrophs in order to boost the competitiveness of industrial CH4-based ectoine production.

Microbial Utilization of Next-Generation Feedstocks for the Biomanufacturing of Value-Added Chemicals and Food Ingredients

“…CH 4 has been used to produce PHAs ( Myung et al, 2017 ), methanol ( Hur et al, 2017 ), single-cell proteins ( Khoshnevisan et al, 2019 ), ectoine ( Cantera et al, 2019 ), lipids ( Fei et al, 2018 ), organic acids [e.g., lactic acid ( Henard et al, 2016 ) and butyric acid ( Garg et al, 2018 )] and terpenoids [e.g., α-humulene and α-bisabolene ( Nguyen et al, 2021 )]. More examples can be found in the recent article ( Gęsicka et al, 2021 ).…”

Ectoine production in bioreactor by Halomonas elongataDSM2581: Using MWCNT and Fe‐nanoparticle

“…Halophilic microorganisms, especially Halomonas spp., have been used for the production of different products in various industrial fields 16,17 . The suitable microorganism for a large‐scale production of ectoines is Halomonas elongata 18 …”

“…15 Halophilic microorganisms, especially Halomonas spp., have been used for the production of different products in various industrial fields. 16,17 The suitable microorganism for a large-scale production of ectoines is Halomonas elongata. 18 The effect of metal nanoparticles on biosurfactant production and bacterial growth is important in various industrial fields.…”