Sustainable bio-plastic production through landfill methane recycling

Poly(3-hydroxybutyrate) (PHB)—a renewable and biodegradable polymer—is a promising alternative to nonbiodegradable synthetic plastics that are derived from petrochemicals. The methods currently employed for PHB production are costly, in part, due to the expensive cultivation feedstocks and the need to sterilize the culture medium, which is energy-intensive. This study investigates the feasibility of nonsterile PHB production from several saline organic wastes using a salt-tolerant strain, Zobellella denitrificans ZD1 (referred to as strain ZD1). Factors such as the pH, salinity, carbon/nitrogen (C/N) ratio, nitrogen source, and electron acceptor that might affect the growth of strain ZD1 and its PHB production were determined. Our results showed successful nonsterile PHB production by growing the strain ZD1 on nonsterile synthetic crude glycerol, high-strength saline wastewater, and real municipal wastewater-activated sludge under saline conditions. The PHB production was significantly enhanced when the levels of salts and nitrate-nitrogen in the culture medium were increased. This study suggested a promising low-cost nonsterile PHB production strategy from organic wastes using strain ZD1.

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“… 2 Although PHB is an environmentally friendly option, its price remains too high to be competitive in the market. 3 …”

Section: Introductionmentioning

confidence: 99%

From Organic Wastes to Bioplastics: Feasibility of Nonsterile Poly(3-hydroxybutyrate) Production by Zobellella denitrificans ZD1

et al. 2020

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“…Current industrial production relies on using sugars as feedstock, which translates into high production costs and competition with food production. A promising alternative involves using methanotrophic bacteria that convert single-carbon compounds into PHB ( Chidambarampadmavathy et al, 2017 ). The use of residual methane and methanol, both low value common industrial by-products, reduces both the costs of production of biomolecules, such as PHB, compared to sugar-based feedstocks ( Fei et al, 2014 ; Strong et al, 2015 ) and carbon emissions from the source industry.…”

Section: Introductionmentioning

confidence: 99%

Defining Nutrient Combinations for Optimal Growth and Polyhydroxybutyrate Production by Methylosinus trichosporium OB3b Using Response Surface Methodology

2018

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Methane and methanol are common industrial by-products that can be used as feedstocks for the production of value-added products by methylotrophic bacteria. Alphaproteobacterial methanotrophs are known to produce and accumulate the biopolymer polyhydroxybutyrate (PHB) under conditions of nutrient starvation. The present study determined optimal production of biomass and PHB by Methylosinus trichosporium OB3b as a function of carbon source (methane or methanol), nitrogen source (ammonium or nitrate), and nitrogen-to-carbon ratio during growth. Statistical regression analysis with interactions was performed to assess the importance of each factor, and their respective interactions, on biomass and PHB production. Higher biomass concentrations were obtained with methane as carbon source and with ammonium as nitrogen source. The nitrogen source that favored PHB production was ammonium for methane-grown cells and nitrate for methanol-grown cells. Response surface methodology (RSM) was used to determine conditions leading to optimal biomass and PHB production. As an example, the optimal PHB concentration was predicted to occur when a mixture of 30% methane and 70% methanol (molar basis) was used as carbon source with nitrate as nitrogen source and a nitrogen-to-carbon molar ratio of 0.017. This was confirmed experimentally, with a PHB concentration of 48.7 ± 8.3 mg/L culture, corresponding to a cell content of 52.5 ± 6.3% (cell dry weight basis). Using RSM to simultaneously interrogate multiple variables toward optimized growth and production of biopolymer serves as a guide for establishing more efficient industrial conditions to convert single-carbon feedstocks into value-added products.

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“…Moreover, if the quantities of urban waste generation continue to rise, especially in the economically advancing countries as is reflected clearly in the trends [2,26], the advantage would soon be offset by the additional emissions. Given this context, the hope expressed by some authors that 'sustainable' bio-plastic can be produced using landfill-derived methane [46,201] or 'renewable energy assets' can be developed by harvesting solar energy falling on landfills [90] appears rather unrealistic. In Europe alone, an estimated 5.25 billion tonnes of MSW has been landfilled between 1995 and 2015, of which plastic is estimated to have contributed over a billion tonnes [37].…”

Section: Capture and Utilization Of Landfill Gasmentioning

confidence: 99%

The myth and the reality of energy recovery from municipal solid waste

Abbasi

2018

Energ Sustain Soc

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Background: Any manner of development can be sustainable only if the waste generated by it is not allowed to accumulate but is fully reused/recycled/recovered. Among the strategies to attain this goal have been the attempts to recover energy from municipal solid waste (MSW). About 60% of MSW is carbonaceous, consisting of materials which can either be biodegraded into fuels like methane or incinerated, thereby generating utilizable energy. MSW also contains several components-like metallic scrap and glass pieces-which can be reused or recycled, thereby achieving energy conservation. Given these attributes, MSW appears to be a potential source of energy and resources. Indeed, this belief that MSW is usable if only we try sincerely enough to do so prompts most of us to keep generating much more MSW than is warranted. But how realizable really is the energy potential of MSW? What perils loom into view when we actually set out to utilize MSW as an energy source? The present study addresses these crucially important questions. Methods: The work is based on a critical content analysis of the prior art. Results: The generation of MSW has consistently outpaced the world's efforts to dispose of it cleanly, and the energy (and material) recovery from MSW is easier said than done. In most instances, what is technically feasible is economically unfeasible. And what is economically feasible-such as setting the waste on fire as is often done in developing countries-is exceedingly harmful to the environment and the human health. Measures such as sanitary landfilling and incineration create as many new problems as the old ones they solve. Moreover, despite the use of these less-than-adequate technologies, a major portion of MSW generated in the world lies untreated. Conclusions: As the MSW output is expected to double by 2025, this situation is only set to become worse. Rising tides of E-waste would compound the problem even further. Hence, enormous stress should be put on the reduction of MSW generation by controlling wanton consumerism and wastage, rather than continuing with it in the false hope that technology will soon provide a magical solution and eliminate the problem.

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Sustainable bio-plastic production through landfill methane recycling

Cited by 96 publications

References 48 publications

From Organic Wastes to Bioplastics: Feasibility of Nonsterile Poly(3-hydroxybutyrate) Production by Zobellella denitrificans ZD1

From Organic Wastes to Bioplastics: Feasibility of Nonsterile Poly(3-hydroxybutyrate) Production by Zobellella denitrificans ZD1

Defining Nutrient Combinations for Optimal Growth and Polyhydroxybutyrate Production by Methylosinus trichosporium OB3b Using Response Surface Methodology

The myth and the reality of energy recovery from municipal solid waste

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