Producing next-generation biofuels from filamentous cyanobacteria: An economic feasibility analysis

Abstract

The need for renewable, sustainable sources of biofuels continues to increase as the world's population continues to grow. Using microorganisms as biofuel producers is one area that is being researched extensively for this purpose. Anabaena sp. PCC 7120 is a filamentous strain of cyanobacteria capable of fixing atmospheric nitrogen, and has been genetically engineered to produce limonene, a cyclic hydrocarbon which has potential as a next-generation biofuel. This study analyzed the economic feasibility of a theoretical next-generation production facility that uses genetically engineered Anabaena 7120 to produce limonene. The economic feasibility of a limonene production facility was analyzed using the Farm-level Algae Risk Model (FARM). This model is an integrated systems compilation of numerous technoeconomic models that has been used previously in several algal production scenarios. FARM simulated 10 years of operation for the production facility for two scenarios. The 1 st scenario used actual limonene productivity data (0.018 mg/L/d) from a genetically engineered strain of filamentous cyanobacteria, while the nd scenario used a 'best case' assumption that limonene productivity can be increased 100-fold (1.8 mg/L/d). It was determined that the average probability of economic success of the 1 st scenario at year 5 was 0%, while the average probability of success of the 2 nd scenario was 100%. Assuming no fractional reductions in OPEX and CAPEX, the average net present value (NPV) at year 5 of the 1 st scenario was-$588 million, compared to $392 million for the 2 nd scenario. Further analysis determined that a limonene productivity of 1.02 mg/L/d is needed to yield an NPV of 0 dollars at year 5. This study shows strong evidence that a next-generation biofuel production facility utilizing genetically engineered strains of filamentous cyanobacteria could become economically feasible in the future if strains are developed with increased biofuel productivities.

Cyanobacteria as an eco‐friendly resource for biofuel production: A critical review

“…Table summarizes the operating cost of limonene production at year 5 of the 10 years simulation. A total cost of $108,075,868 is needed for production of 3,243,300 L/yr limonene in the second scenario . In comparison with the traditional methods, $2,926,000 are required for the production of 800 tonnes/year limonene from citrus waste .…”

“…In comparison with the traditional methods, $2,926,000 are required for the production of 800 tonnes/year limonene from citrus waste . Therefore, the using of engineered cyanobacteria would have economic potential for the biofuel generation in the future . Flocculation is an economical method for biomass recovery; however, usually, one method does not have a similar yield for different microalgae and cyanobacteria.…”

“…A total cost of $108,075,868 is needed for production of 3,243,300 L/yr limonene in the second scenario. 131 In comparison with the traditional methods, $2,926,000 are required for the production of 800 tonnes/year limonene from citrus waste. 132 Therefore, the using of engineered cyanobacteria would have economic potential for the biofuel generation in the future.…”

“…132 Therefore, the using of engineered cyanobacteria would have economic potential for the biofuel generation in the future. 131 Flocculation is an economical method for biomass recovery; however, usually, one method does not have a similar yield for different microalgae and cyanobacteria. Therefore, flocculant dosage is an important factor in the selection of the candidate cyanobacterial isolate to produce biofuel.…”

“…Summary of expenses for the theoretical limonene productionFacility at Year 5 (for first and second scenarios). The limonene productivity was 32,433 L/year and 3,243,300 L/year for the first and second scenarios, respectively [reprinted with permission from Elsevier] 131. …”