Elucidating the key environmental parameters during the production of ectoines from biogas by mixed methanotrophic consortia

Carmona-Martínez, Alessandro A.; Marcos-Rodrigo, Eva; Bordel, Sergio; Marín, David; Herrero-Lobo, Raquel; García‐Encina, Pedro A.; Muñoz, Raúl

doi:10.1016/j.jenvman.2021.113462

Cited by 18 publications

(7 citation statements)

References 42 publications

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“… 25 A specific biomass production yield of 0.4 g biomass · g CH 4 –1 and an ectoine accumulation of 70 mg ectoine· g biomass –1 were chosen according to previous results at laboratory scale. 23 The stoichiometric formulas of biomass and ectoine were C 4 H 8 O 2 N and C 6 H 10 N 2 O 2 , respectively. A mineralization ratio of 0.7 mol CO 2 ·mol CH 4 –1 and an oxygen demand of 1.5 mol O 2 ·mol CH 4 –1 were used according to eqs 1 – 3 : …”

Section: Methodsmentioning

confidence: 99%

“… 23 A NaCl concentration of 6%w·w –1 has been reported in the literature as the optimal salinity for the accumulation of ectoine in haloalkaliphilic methanotrophic cultures. 23 , 24 The bioreactor was operated under continuous mode at a dilution rate of 0.4 d –1 . A mineral medium solution containing 41.0 g NaNO 3 ·L –1 , 82.5 g NaCl·L –1 , and trace concentrations of micronutrients was continuously added to support haloalkaliphilic methanotrophic bacteria growth and ectoine synthesis.…”

Section: Methodsmentioning

confidence: 99%

“…The use of mixed methanotrophic cultures has been demonstrated to be an efficient method supporting long-term operation and process robustness, given its inherent prevention of culture contamination . Despite the fact that the bacterial population structure might be highly variable depending on the inoculum and the culture and environmental conditions, previous work at lab-scale under nonsterile conditions has shown a predominance of ectoine producing methanotrophs such as Methylomicrobium buryatense and Methylomicrobium japanense species in these mixed cultures . A NaCl concentration of 6%w·w –1 has been reported in the literature as the optimal salinity for the accumulation of ectoine in haloalkaliphilic methanotrophic cultures. , The bioreactor was operated under continuous mode at a dilution rate of 0.4 d –1 .…”

Section: Methodsmentioning

confidence: 99%

“…A tungsten concentration of 0.07 mg·L –1 was supplemented to the liquid medium in order to prevent the formation of formic acid, which typically exhibits a significant inhibitory effect on the elimination capacity of methane (CH 4 -EC) . A specific biomass production yield of 0.4 g biomass · g CH 4 –1 and an ectoine accumulation of 70 mg ectoine· g biomass –1 were chosen according to previous results at laboratory scale . The stoichiometric formulas of biomass and ectoine were C 4 H 8 O 2 N and C 6 H 10 N 2 O 2 , respectively.…”

Section: Methodsmentioning

confidence: 99%

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Ectoine Production from Biogas in Waste Treatment Facilities: A Techno-Economic and Sensitivity Analysis

Pérez

Moltó²,

Lebrero

et al. 2021

ACS Sustainable Chem. Eng.

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The capacity of haloalkaliphilic methanotrophic bacteria to synthesize ectoine from CH 4 -biogas represents an opportunity for waste treatment plants to improve their economic revenues and align their processes to the incoming circular economy directives. A techno-economic and sensitivity analysis for the bioconversion of biogas into 10 t ectoine·y –1 was conducted in two stages: (I) bioconversion of CH 4 into ectoine in a bubble column bioreactor and (II) ectoine purification via ion exchange chromatography. The techno-economic analysis showed high investment (4.2 M€) and operational costs (1.4 M€·y –1 ). However, the high margin between the ectoine market value (600–1000 €·kg –1 ) and the estimated ectoine production costs (214 €·kg –1 ) resulted in a high profitability for the process, with a net present value evaluated at 20 years (NPV 20 ) of 33.6 M€. The cost sensitivity analysis conducted revealed a great influence of equipment and consumable costs on the ectoine production costs. In contrast to alternative biogas valorization into heat and electricity or into low added-value bioproducts, biogas bioconversion into ectoine exhibited high robustness toward changes in energy, water, transportation, and labor costs. The worst- and best-case scenarios evaluated showed ectoine break-even prices ranging from 158 to 275 €·kg –1 , ∼3–6 times lower than the current industrial ectoine market value.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Ectoine Production from Biogas in Waste Treatment Facilities: A Techno-Economic and Sensitivity Analysis

Pérez

Moltó²,

Lebrero

et al. 2021

ACS Sustainable Chem. Eng.

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“…Methanotrophs have recently emerged as a prominent solution for methane mitigation and value-added resources recovery platform in wastewater treatment technology (AlSayed et al, 2018). A recent published study also demonstrated methane bioconversion into ectoine, a valuable compound in the cosmetic and medical industry, using mixed methanotrophic consortia (Carmona- Martínez et al, 2021). AlSayed et al (2018) summarized the potential of biogas utilization by methanotrophs in comparison with ammonia-oxidizing bacteria that can also utilize methane and activate its stable C-H bond, as shown in Figure 2.5.…”

Section: Dissolved Methane Removal From Anaerobic Effluentmentioning

confidence: 99%

Low-temperature anaerobic wastewater treatment by granulated biomass

Safitri¹

2022

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In this study, long-term operation of up-flow anaerobic sludge blanket (UASB) system treating real municipal wastewater at decreasing temperatures (25, 16, 12, 8.5, 5.5, and 2.5 °C) and variable organic loading rates from 1.0 gCOD·l⁻¹·d⁻¹ up to 15.2 gCOD·l⁻¹·d⁻¹ was investigated over 1025 days. Experiments were performed in two parallel in-house designed laboratory-scale UASB reactors, which were operated continuously with hydraulic retention time of 16.7 h down to 1.1 h. Stable COD removal efficiencies of 50 - 70 % were achieved at 25 °C down to 8.5 °C with loading up to approximately 15.2 gCOD·l-1·d-1. COD removal efficiencies were reduced at temperatures below 8.5 °C, but significant methane formation was observed even at 2.5 °C at reduced loading (up to 5 gCOD·l-1·d-1). More than 90% of COD removed was converted to methane, and the methane yield did not change significantly with respect to temperatures. The overall COD balance closed at above 90% of the inlet COD at all operating temperatures and organic loading rates. Temperature affected the reactor performances, microbial community structure, and the degradation pathway of organic matter with acetoclastic methanogen played significant roles. Acetate was the primary precursor of methanogenesis pathway at low-temperatures. Microbial communities proved the adaptation ability to very low-temperatures down to 2.5 °C regardless of the operating organic loading rates; psychrotolerant. Additionally, an anaerobic granulated biofilm system at 25 °C and different organic loading rates (1, 3, 8, 10, 15, and 20 gCOD·l-1·d-1) was modelled in AQUASIM 2.1 to predict and simulate biofilm model implementation and assumptions specific to the granules as a fixed biofilm in UASB reactor system in this study. Simulated organic loading rates scenario results showed COD removal efficiencies (62 - 69%) and methane fraction (83 - 88%) in biogas at steady-state conditions decreased with the increasing organic loading rates. All simulations predicted an increased pH profile, from pH 7 in the outer layer to approximately pH 8.3 in the core of granules, under increasing organic loading rates, but the biomass composition and active biofilm regions were not significantly affected by organic loading rate variable. UASB effluent post-treatment investigations, specifically on dissolved methane and nutrient removal, were performed as supplementary studies. A methanotrophic-cyanobacterial syntrophy was established in the existing oxygenic photogranules to remove dissolved methane. This syntrophy was maintained and propagated in a continuously operated reactor (hydraulic retention time of 12 h), proven by observed biomass yield and dissolved methane removal by approximately 2.4 gVSS·gCH₄⁻¹ and 85%, respectively, with COD balance closed at around 91%. Community analysis suggested methanotrophs and phototrophs syntrophy, and the cross-feeding between photogranules of different community compositions, containing methanotrophic bacteria, phototrophs, and non-methanotrophic methylotrophs. Nutrient removal from filtered UASB secondary effluent was investigated using several microalgal strains based on a literature review: Chlorella vulgaris, Chlorella sorokiniana, Tetradesmus obliquus, Haematococcus pluvialis, and Microchloropsis salina. Microalgae strain C. sorokiniana presented the ability to grow in wastewater in all the tested culture conditions, suggesting high adaptability and viability of the strain in this specific type of filtered UASB secondary effluent. The results also implied nutrient removal achieved 62% of total nitrogen removal and 97% of total phosphorous removal, when applying C. sorokiniana in the batch systems with hydraulic retention time of 9 days. The growth potential and the nutrient removal capacity of C. sorokiniana in a continuous laboratory-scale photobioreactor were also investigated. The system removed total nitrogen and total phosphorous by approximately 17% and 27%, respectively, with hydraulic retention time of 5.5 days. High ammonium removal yet high nitrate release indicated microalgae-nitrifiers imbalance in the photobioreactor system. Unfavorable growth factor for microalgae in the photobioreactor could be carbon-limited media in wastewater (2C:22N:1P). Adding an external source of CO2 to control alkalinity, pH, and provide carbon source for microalgal growth is most probably needed for further investigation. Even though nutrient removal efficiencies in continuous photobioreactor were significantly lower than the batch test, biomass yield in the photobioreactor was higher (0.16±0.02 gTNremoved∙gSS-1 and 0.03±0.005 gTPremoved∙gSS-1), compared to the batch test (0.04±0.01 gTNremoved∙gSS-1 and 0.02±0.002 gTPremoved∙gSS-1). High biomass production suggested that microalgal-based treatment for UASB effluent could offer a resource recovery potential. Overall, this study demonstrated the feasibility of UASB system treating municipal wastewater at low-temperatures and variable loadings in a long-term application. In combination with suitable post-treatments, UASB system showed a viable secondary pre-treatment option unit process for achieving lower carbon footprint wastewater treatment and resource recovery at low-temperatures. The robustness exhibited to low-temperature and variable loading conditions provides a solid basis for further research and potential applications. Further advances in an integrated UASB system and post-treatment unit processes investigation will be needed for pilot- and/or full-scale applications in the future.

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Production of hydroxyectoine from biogas by an engineered strain of Methylomicrobium alcaliphilum using a novel Taylor‐flow bioreactor

Herrero‐Lobo,

Fernández‐González,

Marcos

et al. 2024

J of Chemical Tech & Biotech

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BACKGROUNDThe production of compatible solutes, such as ectoine and hydroxyectoine, is of great interest due to their industrial and biotechnological applications. Methylomicrobium alcaliphilum was genetically engineered to replace a native gene with a heterologous one, aiming to enhance ectoine production. This study focuses on the optimization of bioreactor conditions to maximize the microbial production of these metabolites from methane.RESULTSThe engineered strain (M. alcaliphilum PstEctD) was cultured in a Taylor flow bioreactor under varying gas recirculation flow rates. Increased flow rates enhanced methane consumption, biomass concentration, and ectoine production. The highest production of ectoine (32 mg/g‐VSS) and hydroxyectoine (272 mg/g‐VSS) was observed at a flow rate of 0.7 L min−1, while methane removal efficiency improved from 30% to over 60% as flow rates increased.CONCLUSIONSOptimizing bioreactor conditions, particularly gas recirculation flow rates, significantly improved both the efficiency of methane consumption and the production of ectoine derivatives. This work provides a scalable approach for the sustainable production of compatible solutes from methane, offering potential applications in biotechnological processes utilizing renewable carbon sources. © 2024 The Author(s). Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).

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Elucidating the key environmental parameters during the production of ectoines from biogas by mixed methanotrophic consortia

Cited by 18 publications

References 42 publications

Ectoine Production from Biogas in Waste Treatment Facilities: A Techno-Economic and Sensitivity Analysis

Ectoine Production from Biogas in Waste Treatment Facilities: A Techno-Economic and Sensitivity Analysis

Low-temperature anaerobic wastewater treatment by granulated biomass

Production of hydroxyectoine from biogas by an engineered strain of Methylomicrobium alcaliphilum using a novel Taylor‐flow bioreactor

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