Photosynthetic terpene hydrocarbon production for fuels and chemicals

Wang, Xin; Ort, Donald R.; Yuan, Joshua S.

doi:10.1111/pbi.12343

Cited by 49 publications

(37 citation statements)

References 121 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The lower biomass yield would probably cause the increase of lipid‐cane price to balance farmer's income. However, it would also be very possible that biomass might increase due to the synergy effect of lipid accumulation and carbon assimilation and current research on photosynthesis improvements of crops . Therefore, a larage variation of lipid‐cane price ($25 to $45/MT) was selected for sensivitiy analysis.…”

Section: Resultsmentioning

confidence: 99%

Techno‐economic analysis of biodiesel and ethanol co‐production from lipid‐producing sugarcane

Huang

Long

Singh

2016

Biofuels Bioprod Bioref

119

View full text Add to dashboard Cite

Biodiesel production from vegetable oils has progressively increased over the past two decades. However, due to the low amounts of oil produced per hectare from temperate oilseed crops (e.g. soybean), the opportunities for further increasing biodiesel production are limited. Genetically modifi ed lipid-producing sugarcane (lipid-cane) possesses great potential for producing biodiesel as an alternative feedstock because of sugarcane's much higher productivity compared with soybean. In this study, techno-economic models were developed for biodiesel and ethanol coproduction from lipid-cane, assuming 2, 5, 10, or 20% lipid concentration in the harvested stem (dry mass basis). The models were compared with a conventional soybean biodiesel process model to assess lipid-cane's competiveness. In the lipid-cane process model, the extracted lipids were used to produce biodiesel by transesterifi cation, and the remaining sugar was used to produce ethanol by fermentation. The results showed that the biodiesel production cost from lipid-cane decreased from $0.89/L to $0.59 /L as the lipid content increased from 2 to 20%; this cost was lower than that obtained for soybeans ($1.08/L). The ethanol production costs from lipid-cane were between $0.40/L and $0.46/L. The internal rate of return (IRR) for the soybean biodiesel process was 15.0%, and the IRR for the lipid-cane process went from 13.7 to 24.0% as the lipid content increased from 2 to 20%. Because of its high productivity, lipid-cane with 20% lipid content can produce 6700 L of biodiesel from each hectare of land, whereas soybean can only produce approximately 500 L of biodiesel from each hectare of land. This would indicate that continued efforts to achieve lipid-producing sugarcane could make large-scale replacement of fossil-fuelderived diesel without unrealistic demands on land area.

show abstract

Section: Resultsmentioning

confidence: 99%

Techno‐economic analysis of biodiesel and ethanol co‐production from lipid‐producing sugarcane

Huang

Long

Singh

2016

Biofuels Bioprod Bioref

119

View full text Add to dashboard Cite

show abstract

“…Terpenes are synthesized from two C 5 precursor molecules, isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP). In cyanobacteria, IPP and DMAPP are derived from the MEP pathway, where glyceraldehyde 3-phosphate (G3P) and pyruvate are condensed into the C 5 precursors through seven enzymatic steps (2) (Fig. 1A).…”

Section: Stepwise Metabolic Engineering Is Limited In Enhancing Limonmentioning

confidence: 99%

“…Earlier approaches often involved overexpressing pathway enzymes to enhance carbon flux, but these approaches were hindered by the limited understanding of metabolic network and its regulation. In particular, many low-flux pathways (e.g., terpene biosynthesis) impede carbon partition due to metabolic rigidity (2,3). Moreover, the importance and requirement of energy balance in improving photosynthetic productivity (4), is often neglected in engineering efforts.…”

mentioning

confidence: 99%

“…Moreover, the importance and requirement of energy balance in improving photosynthetic productivity (4), is often neglected in engineering efforts. Recently, a few studies have demonstrated the possibility of producing terpenes in cyanobacteria, but the productivity is rather low (2,(5)(6)(7). Enhancing carbon flux into a low-flux terpene pathway could provide intuitive insight to both carbon partition and photosynthesis regulations.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Enhanced limonene production in cyanobacteria reveals photosynthesis limitations

Wang

Liu

Xin

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

144

View full text Add to dashboard Cite

Terpenes are the major secondary metabolites produced by plants, and have diverse industrial applications as pharmaceuticals, fragrance, solvents, and biofuels. Cyanobacteria are equipped with efficient carbon fixation mechanism, and are ideal cell factories to produce various fuel and chemical products. Past efforts to produce terpenes in photosynthetic organisms have gained only limited success. Here we engineered the cyanobacterium Synechococcus elongatus PCC 7942 to efficiently produce limonene through modeling guided study. Computational modeling of limonene flux in response to photosynthetic output has revealed the downstream terpene synthase as a key metabolic flux-controlling node in the MEP (2-C-methyl-D-erythritol 4-phosphate) pathway-derived terpene biosynthesis. By enhancing the downstream limonene carbon sink, we achieved over 100-fold increase in limonene productivity, in contrast to the marginal increase achieved through stepwise metabolic engineering. The establishment of a strong limonene flux revealed potential synergy between photosynthate output and terpene biosynthesis, leading to enhanced carbon flux into the MEP pathway. Moreover, we show that enhanced limonene flux would lead to NADPH accumulation, and slow down photosynthesis electron flow. Fine-tuning ATP/NADPH toward terpene biosynthesis could be a key parameter to adapt photosynthesis to support biofuel/ bioproduct production in cyanobacteria.photosynthesis | limonene | advanced biofuel | terpene | MEP E fficient carbon partition into desired molecules is a major scientific challenge in producing chemicals in photosynthetic organisms (1). Earlier approaches often involved overexpressing pathway enzymes to enhance carbon flux, but these approaches were hindered by the limited understanding of metabolic network and its regulation. In particular, many low-flux pathways (e.g., terpene biosynthesis) impede carbon partition due to metabolic rigidity (2, 3). Moreover, the importance and requirement of energy balance in improving photosynthetic productivity (4), is often neglected in engineering efforts. Recently, a few studies have demonstrated the possibility of producing terpenes in cyanobacteria, but the productivity is rather low (2, 5-7). Enhancing carbon flux into a low-flux terpene pathway could provide intuitive insight to both carbon partition and photosynthesis regulations. Through computational modeling, we show that downstream limonene synthase is a key flux-controlling node in the 2-C-methyl-Derythritol 4-phosphate (MEP)-derived limonene biosynthesis in cyanobacteria. Overcoming this metabolic bottleneck led to a record limonene productivity in the engineered cyanobacteria. Moreover, we show that enhanced limonene production led to redox change and energy imbalance, which ultimately limit photosynthesis capacity. The study demonstrates a successful strategy to enhance carbon partition into MEP-derived terpene biosynthesis, and reveals key photosynthesis regulations in providing ATP/NADPH to support terpene production. Stepwise M...

show abstract

“…Terpenes are highly combustible, and the large amounts of terpenoids stored in trees, such as conifers in the Northern hemisphere and eucalypts in Australia, exacerbate forest fires and help them to spread more easily. The combustibility of terpenoids has led to the suggestion, as well as some initial work, that certain terpenes, particularly those that are liquid at ambient temperature, could be produced in biological systems for fuel (Wang et al, 2015). Some progress has also been achieved towards the genetic engineering of microorganisms to produce a variety of terpenoid drugs, such as taxol, vinblastine and artemisinin (for malaria prevention), as well as a variety of fragrances and flavor compounds, such as valencene and patchoulol (Schwab et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Why do plants produce so many terpenoid compounds?

2016

View full text Add to dashboard Cite

All plants synthesize a suite of several hundred terpenoid compounds with roles that include phytohormones, protein modification reagents, anti-oxidants, and more. Different plant lineages also synthesize hundreds of distinct terpenoids, with the total number of such specialized plant terpenoids estimated in the scores of thousands. Phylogenetically restricted terpenoids are implicated in defense or in the attraction of beneficial organisms. A popular hypothesis is that the ability of plants to synthesize new compounds arose incrementally by selection when, as a result of gradual changes in their biotic partners and enemies, the 'old' plant compounds were no longer effective, a process dubbed the 'coevolutionary arms race'. Another hypothesis posits that often the sheer diversity of such compounds provides benefits that a single compound cannot. In this article, we review the unique features of the biosynthetic apparatus of terpenes in plants that facilitate the production of large numbers of distinct terpenoids in each species and how facile genetic and biochemical changes can lead to the further diversification of terpenoids. We then discuss evidence relating to the hypotheses that given ecological functions may be enhanced by the presence of mixtures of terpenes and that the acquisition of new functions by terpenoids may favor their retention once the original functions are lost.

show abstract

Photosynthetic terpene hydrocarbon production for fuels and chemicals

Cited by 49 publications

References 121 publications

Techno‐economic analysis of biodiesel and ethanol co‐production from lipid‐producing sugarcane

Techno‐economic analysis of biodiesel and ethanol co‐production from lipid‐producing sugarcane

Enhanced limonene production in cyanobacteria reveals photosynthesis limitations

Why do plants produce so many terpenoid compounds?

Contact Info

Product

Resources

About