Biopolymers made from methane in bioreactors

Chidambarampadmavathy, Karthigeyan; Karthikeyan, Obulisamy Parthiba; Heimann, Kirsten

doi:10.1002/elsc.201400203

Cited by 26 publications

(3 citation statements)

References 90 publications

(184 reference statements)

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“…At their end life, these bioplastics are degraded back to CO 2 to produce a closed cycle . However, this process is associated with high energy and cost demands (30–50% of the production cost) associated with the cultivated crops , . Therefore, developing a new reliable feedstock with a cheaper production process, such as wastewater, biogas methane and carbon dioxide, is a key milestone in the scale up of biopolymers production.…”

Section: Introductionmentioning

confidence: 99%

Factors affecting the selection of PHB accumulating methanotrophs from waste activated sludge while utilizing ammonium as their nitrogen source

Fergala

Alsayed

Eldyasti

2017

J of Chemical Tech & Biotech

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BACKGROUND Methanotrophs can offer a long‐term reliable solution to two of the major problems causing environmental pollution. These microorganisms can convert methane, i.e. second major greenhouse gas (GHG), into biodegradable polymers as polyhydroxybutyrate (PHB). In this research, waste activated sludge was used as a seed for cultivating enrichments utilizing methane and ammonium as their sole carbon and nitrogen sources respectively with high PHB accumulation capacity. Moreover, to test the effect of different parameters, such as the initial ratio between the ammonium and the microorganisms (N/M), food to microorganisms ratio (F/M), the solids retention time (SRT), copper elimination and nitrate, on the selection of PHB accumulating, i.e. Type II methanotrophs. RESULTS After establishing a mixed culture dominated by Type II methanotrophs, the enriched culture was kept in the exponential phase of growth and had a stable performance for almost 30 consecutive cycles with a specific growth rate of 0.077 ± 0.005 h‐1 and biomass yield of 0.81 ± 0.06 mg‐VSS mg‐1‐CH4. The PHB accumulation capacity of the enrichment reached 52.9 ± 4% with a yield of 0.54 ± 0.12 mg‐PHB mg‐1‐CH4. CONCLUSIONS Increasing the N/M ratio can be employed to ensure the dominance of Type II methanotrophs in mixed cultures having high PHB accumulation capacity while maintaining a high F/M ratio overcomes any inhibition resulting from ammonium co‐metabolism. Despite the dominance of Type II, switching the nitrogen source to nitrate caused an invasion of Type I methanotrophs and a deterioration in the PHB accumulation of the enriched culture. © 2017 Society of Chemical Industry

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Section: Introductionmentioning

confidence: 99%

Factors affecting the selection of PHB accumulating methanotrophs from waste activated sludge while utilizing ammonium as their nitrogen source

Fergala

Alsayed

Eldyasti

2017

J of Chemical Tech & Biotech

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“…The benefits of bacterial consortia of methanotrophs and het-erotrophs have been noted, for example, in the production of microbial proteins by methanotrophs [30,83]. Other researchers have demonstrated that consortia are more efficient than pure cultures in the production of valuable compounds e.g., polymers (PHAs) [84,85] or ectoine [86]. The presence of heterotrophs ensures culture stabilization by consuming potentially inhibitory metabolic byproducts or contaminants [87].…”

Section: The Importance Of Microorganism Community In Biotechnologymentioning

confidence: 99%

Dynamics of Methane-Consuming Biomes from Wieliczka Formation: Environmental and Enrichment Studies

Goraj,

Pytlak,

Grządziel

et al. 2023

Biology

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The rocks surrounding Wieliczka salt deposits are an extreme, deep subsurface ecosystem that as we studied previously harbors many microorganisms, including methanotrophs. In the presented research bacterial community structure of the Wieliczka Salt Mine was determined as well as the methanotrophic activity of the natural microbiome. Finally, an enrichment culture of methane-consuming methanotrophs was obtained. The research material used in this study consisted of rocks surrounding salt deposits in the Wieliczka Salt Mine. DNA was extracted directly from the pristine rock material, as well as from rocks incubated in an atmosphere containing methane and mineral medium, and from a methanotrophic enrichment culture from this ecosystem. As a result, the study describes the composition of the microbiome in the rocks surrounding the salt deposits, while also explaining how biodiversity changes during the enrichment culture of the methanotrophic bacterial community. The contribution of methanotrophic bacteria ranged from 2.614% in the environmental sample to 64.696% in the bacterial culture. The methanotrophic enrichment culture was predominantly composed of methanotrophs from the genera Methylomonas (48.848%) and Methylomicrobium (15.636%) with methane oxidation rates from 3.353 ± 0.105 to 4.200 ± 0.505 µmol CH4 mL−1 day−1.

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“…There are a great many studies that have explored the relative merits of mixed cultures versus pure strains for PHA accumulation in general, including some that are specific to the use of methane as a carbon source [ 14 , 58 , 70 , 91 , 92 , 93 , 94 ]. Overall, these studies suggest that such mixed cultures may provide specific benefits such as: co-culture bacteria removing potentially toxic byproducts (e.g., methanol or formaldehyde) from the medium; beneficial nutrients being supplied by co-culture bacteria; operation under non-sterile conditions; and even possibly higher yields and production rates.…”

Section: Process Conditions For Phb Production From Methanementioning

confidence: 99%

The Opportunity for High-Performance Biomaterials from Methane

et al. 2016

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Polyhydroxyalkanoate (PHA) biopolymers are widely recognised as outstanding candidates to replace conventional petroleum-derived polymers. Their mechanical properties are good and can be tailored through copolymer composition, they are biodegradable, and unlike many alternatives, they do not rely on oil-based feedstocks. Further, they are the only commodity polymer that can be synthesised intracellularly, ensuring stereoregularity and high molecular weight. However, despite offering enormous potential for many years, they are still not making a significant impact. This is broadly because commercial uptake has been limited by variable performance (inconsistent polymer properties) and high production costs of the raw polymer. Additionally, the main type of PHA produced naturally is poly-3-hydroxybutyrate (PHB), which has limited scope due to its brittle nature and low thermal stability, as well as its tendency to embrittle over time. Production cost is strongly impacted by the type of the feedstock used. In this article we consider: the production of PHAs from methanotrophs using methane as a cost-effective substrate; the use of mixed cultures, as opposed to pure strains; and strategies to generate a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer (PHBV), which has more desirable qualities such as toughness and elasticity.

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Biopolymers made from methane in bioreactors

Cited by 26 publications

References 90 publications

Factors affecting the selection of PHB accumulating methanotrophs from waste activated sludge while utilizing ammonium as their nitrogen source

Factors affecting the selection of PHB accumulating methanotrophs from waste activated sludge while utilizing ammonium as their nitrogen source

Dynamics of Methane-Consuming Biomes from Wieliczka Formation: Environmental and Enrichment Studies

The Opportunity for High-Performance Biomaterials from Methane

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