Abstract:The demand for ammonia is expected to increase in the future because of its importance in agriculture, industry, and hydrogen transportation. Although the Haber–Bosch process is known as an effective way to produce ammonia, the process is energy-intensive. Thus, an environmentally friendly ammonia production process is desired. In this study, we aimed to produce ammonia from amino acids and amino acid-based biomass-like resources by modifying the metabolism of Escherichia coli. By engineering metabolic flux to… Show more
“…In this study, we displayed glutaminase, YbaS, on the yeast cell surface to produce ammonia from glutamine included in pretreated soybean residues outside the cells. Figure 3 shows that YbaSdisplaying yeast produced 3.34 g/L ammonia, which was 1.4 times and 7.3 times higher than the ammonia concentration in the previous studies by metabolically engineered B. subtilis and E. coli (Choi et al 2014;Mikami et al 2017). Therefore, we succeeded in producing highconcentration ammonia using yeast for the first time.…”
Section: Discussionmentioning
confidence: 75%
“…However, there are few reports of successful biological technologies for the sustainable utilization of nitrogen (Vong et al 2016). Some bacteria producing ammonia from biomass were previously created with metabolic engineering (Choi et al 2014;Mikami et al 2017). Disruption of the genes related to assimilation and overexpression of the genes catabolizing amino acids were effective for producing ammonia.…”
Section: Introductionmentioning
confidence: 99%
“…Disruption of the genes related to assimilation and overexpression of the genes catabolizing amino acids were effective for producing ammonia. However, nitrogen compounds such as amino acids and ammonia are essential nutrients for microorganisms and can be used for their growth before their secretion outside of cells (Choi et al 2014;Mikami et al 2017). Moreover, a high concentration of ammonia is toxic to living organisms (Bittsanszky et al 2015;Muller et al 2006;Santos et al 2012).…”
Ammonia is an essential substance for agriculture and the chemical industry. The intracellular production of ammonia in yeast (Saccharomyces cerevisiae) by metabolic engineering is difficult because yeast strongly assimilates ammonia, and the knockout of genes enabling this assimilation is lethal. Therefore, we attempted to produce ammonia outside the yeast cells by displaying a glutaminase (YbaS) from Escherichia coli on the yeast cell surface. YbaS-displaying yeast successfully produced 3.34 g/L ammonia from 32.6 g/L glutamine (83.2% conversion rate), providing it at a higher yield than in previous studies. Next, using YbaS-displaying yeast, we also succeeded in producing ammonia from glutamine in soybean residues (okara) produced as food waste from tofu production. Therefore, ammonia production outside cells by displaying ammonia-lyase on the cell surface is a promising strategy for producing ammonia from food waste as a novel energy resource, thereby preventing food loss.
“…In this study, we displayed glutaminase, YbaS, on the yeast cell surface to produce ammonia from glutamine included in pretreated soybean residues outside the cells. Figure 3 shows that YbaSdisplaying yeast produced 3.34 g/L ammonia, which was 1.4 times and 7.3 times higher than the ammonia concentration in the previous studies by metabolically engineered B. subtilis and E. coli (Choi et al 2014;Mikami et al 2017). Therefore, we succeeded in producing highconcentration ammonia using yeast for the first time.…”
Section: Discussionmentioning
confidence: 75%
“…However, there are few reports of successful biological technologies for the sustainable utilization of nitrogen (Vong et al 2016). Some bacteria producing ammonia from biomass were previously created with metabolic engineering (Choi et al 2014;Mikami et al 2017). Disruption of the genes related to assimilation and overexpression of the genes catabolizing amino acids were effective for producing ammonia.…”
Section: Introductionmentioning
confidence: 99%
“…Disruption of the genes related to assimilation and overexpression of the genes catabolizing amino acids were effective for producing ammonia. However, nitrogen compounds such as amino acids and ammonia are essential nutrients for microorganisms and can be used for their growth before their secretion outside of cells (Choi et al 2014;Mikami et al 2017). Moreover, a high concentration of ammonia is toxic to living organisms (Bittsanszky et al 2015;Muller et al 2006;Santos et al 2012).…”
Ammonia is an essential substance for agriculture and the chemical industry. The intracellular production of ammonia in yeast (Saccharomyces cerevisiae) by metabolic engineering is difficult because yeast strongly assimilates ammonia, and the knockout of genes enabling this assimilation is lethal. Therefore, we attempted to produce ammonia outside the yeast cells by displaying a glutaminase (YbaS) from Escherichia coli on the yeast cell surface. YbaS-displaying yeast successfully produced 3.34 g/L ammonia from 32.6 g/L glutamine (83.2% conversion rate), providing it at a higher yield than in previous studies. Next, using YbaS-displaying yeast, we also succeeded in producing ammonia from glutamine in soybean residues (okara) produced as food waste from tofu production. Therefore, ammonia production outside cells by displaying ammonia-lyase on the cell surface is a promising strategy for producing ammonia from food waste as a novel energy resource, thereby preventing food loss.
“…A driving force for deamination would allow more carbon skeletons to be released from amino acids for product formation, and the strategies for creating the driving force have been well demonstrated in E. coli by Huo et al (Huo et al, 2011). It was shown that deamination could be facilitated by deletion of genes related to ammonium-assimilation pathway (Huo et al, 2011; Mikami et al, 2017). Furthermore, introduction of exogenous transamination-deamination cycles further drained amino acids that serve as nitrogen reservoir as the result of transamination…”
AbstractMetabolic engineering can be used as a powerful tool to redirect cell resources towards product synthesis, also in conditions that are not optimal. An example of a synthesis pathway strongly dependent on external conditions is the production of storage lipids, which typically requires high carbon/nitrogen ratio. Acinetobacter baylyi ADP1 is known for its ability to produce industrially interesting storage lipids, namely wax esters (WEs). Here, we engineered the central carbon metabolism of A. baylyi ADP1 by deletion of the gene aceA encoding for isocitrate lyase in order to allow redirection of carbon towards WEs. The production was further enhanced by overexpression of fatty acyl-CoA reductase Acr1 in the wax ester production pathway. This strategy led to 3-fold improvement in yield (0.075 g/g glucose) and 3.15-fold improvement in titer (1.82 g/L) and productivity (0.038 g/L/h) by a simple one-stage batch cultivation with glucose as carbon source. The engineered strain accumulated up to 27% WEs of cell dry weight. The titer and cellular WE content are the highest reported to date among microbes. We further showed that the engineering strategy alleviated the inherent requirement for high carbon/nitrogen ratio and demonstrated the production of wax esters using nitrogen-rich substrates including casamino acids, yeast extract and baker’s yeast hydrolysate, which support biomass production but not WE production in wild-type cells. The study demonstrates the power of metabolic engineering in overcoming natural limitations in the production of storage lipids.
“…Recently, the same idea has been applied for production of biofuels from DDGS by a bacterial consortium which consists of two strains designed for selective utilization of carbohydrates and amino acids, respectively [ 115 ]. The strategy by deamination of amino acids has also been exploited for the production of ammonia [ 116 ]. Fig.…”
Section: Bio-based Production Of Fuels and Chemicals From Amino Acidsmentioning
To mitigate the climate change caused by CO2 emission, the global incentive to the low-carbon alternatives as replacement of fossil fuel-derived products continuously expands the need for renewable feedstock. There will be accompanied by the generation of enormous protein waste as a result. The economical viability of the biorefinery platform can be realized once the surplus protein waste is recycled in a circular economy scenario. In this context, the present review focuses on the current development of biotechnology with the emphasis on biotransformation and metabolic engineering to refine protein-derived amino acids for production of fuels and chemicals. Its scope starts with the explosion of potential feedstock sources rich in protein waste. The availability of techniques is applied for purification and hydrolysis of various feedstock proteins to amino acids. Useful lessons are leaned from the microbial catabolism of amino acids and lay a foundation for the development of the protein-based biotechnology. At last, the future perspective of the biorefinery scheme based on protein waste is discussed associated with remarks on possible solutions to overcome the technical bottlenecks.
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