Engineering topics
Karanjikar, Mukund
Publications and source records attributed to Karanjikar, Mukund.
A sustainable aviation fuel pathway from biomass: life cycle environmental and cost evaluation for dimethylcyclooctane jet fuel
Biomass is a promising renewable feedstock for conversion to high performance sustainable aviation fuel (SAF) to mitigate greenhouse gas emissions in air travel.
ABF DFO with Technology Holding, Inc.
This Agile BioFoundry Directed Funding Opportunity project with Technology Holding and partners focuses on the development of both a strain of Pseudomonas putida KT2440 and a corresponding bioprocess to convert cellulosic sugars to beta-ketoadipic acid, which can be used in performance nylons and polyesters. Our approach follows the Design-Build-Test-Learn cycle wherein we have transferred learnings from muconic acid production in P. putida to develop a glucose and xylose-utilizing beta-ketoadipic acid production strain. This strain achieves 65 g/L of beta-ketoadipic acid at 0.7 g/L/hr and a C-mol yield of 0.40. We are currently on-boarding arabinose utilization as well. To identify non-intuitive strain modifications as well, we are deploying a beta-ketoadipic acid biosensor and building randomly barcoded transposon insertion sequencing (RB-TnSeq) libraries and gene over-expression libraries in beta-ketoadipic acid production strains. Moreover, we are using global metabolomics and other systems biology tools to identify off-target pathways. Lastly, we are scaling up beta-ketoadipic acid production to kg-scale production for Technology Holding to evaluate in performance polymers with their partners.
Meeting sustainable aviation fuel policy targets through first generation corn biorefineries
This paper investigates options to produce low carbon and renewable aviation fuel through existing commercial first generation biorefineries, which could be strategic given the rapid growth of the electric vehicle market for personal mobility. We evaluate the environmental impact of retrofitting a first generation biorefinery to produce aviation fuel through chemical process simulation. The analysis investigates the potential for reducing greenhouse gas (GHG) emissions and displacing fossil fuel (petroleum-based jet kerosene) in the aviation fuel industry through using corn feedstocks in dry grind biorefineries to convert sugars to 1,4-dimethylcyclooctane (DMCO), which qualifies as renewable jet-A fuel blend and is infrastructure compatible. Further, the average life cycle GHG emissions for a baseline case and a scenario with carbon capture and storage (CCS) of fermentative CO 2 are 36 and 5g CO 2 e/MJ DMCO, respectively. Investment in CCS at the biorefinery and adoption of crop best management practices on farms are essential for mitigating the risks of induced land use change GHG emissions for existing corn biorefineries. DMCO as a low-carbon aviation fuel could be a strategic fuel product for retrofitting existing corn dry grind facilities. For aviation fuel supply, corn dry grind facilities could displace about 12% of jet fuel demand in the near term, which would meet sustainable aviation fuel policy targets. We conclude that corn-to-DMCO shows promise for near-term low-carbon fuel markets in the aviation industry and as a bridge to developing biomass-based jet fuel in the future.
Novel method for biomass conversion to 5 carbon alcohols
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Bio-Based Polyisoprene Can Mitigate Climate Change and Deforestation in Expanding Rubber Production
Biomass is a promising renewable feedstock to produce polyisoprene for the rubber industry. Through metabolic engineering, sugars derived from pretreated and hydrolyzed cellulose and hemicellulose can be directly fermented to isoprene to produce rubber. Here we investigate the life cycle environmental impact of isoprene fermentation to produce bio-polyisoprene from agricultural residues (of Zea mays L.). Results show that the greenhouse gas (GHG) intensity of bio-polyisoprene (−4.59 kg CO2e kg−1) is significantly lower than that of natural rubber (Hevea brasiliensis) and synthetic rubber (−0.79 and 2.41 kg CO2e kg−1, respectively), while supporting a circular biogenic carbon economy. We found the land use intensity of bio-polyisoprene to be 0.25 ha metric ton−1, which is 84% lower than that from rubber tree plantations. We compare the direct fermentation to isoprene results with indirect fermentation to isoprene through the intermediate, methyl butyl ether, where dehydration to isoprene is required. The direct fermentation of isoprene reduces reaction steps and unit operations, an expected outcome when employing process intensification, but our results show additional energy conservation and reduced contribution to climate change. Among the ReCiPe life cycle environmental impact metrics evaluated, air emission related impacts are high for bio-polyisoprene compared to those for natural and synthetic rubber. Those impacts can be reduced with air emission controls during production. All other metrics showed an improvement for bio-polyisoprene compared to natural and synthetic rubber.
Hydrogen utilization and carbon recovery
A method for upgrading bio-mass material is provided. The method involves electrolytic reduction of the material in an electrochemical cell having a ceramic, oxygen-ion conducting membrane, where the membrane includes an electrolyte. One or more oxygenated or partially-oxygenated compounds are reduced by applying an electrical potential to the electrochemical cell. A system for upgrading bio-mass material is also disclosed.
Novel Electro-Deoxygenation Process for Bio-oil Upgrading
Biomass is a potential source of renewable fuel. Bio-oil produced by fast pyrolysis is a prospective option to replace fossil fuels for transportation. However, bio-oil needs to be upgraded to remove its high oxygen and water content, and acidity to produce useful fuels. The upgrading of bio-oil is generally accomplished by hydrodeoxygenation (HDO) using hydrogen. The instability of bio-oil poses a major challenge in transportation to central upgrading facility. An electro-deoxygenation (EDOx) process was evaluated to fully or partially deoxygenate bio-oil using solid oxide electrolysis process. This device uses an oxygen ion conducting membrane which under an applied electric potential removes oxygen in the form of an ion and transports it to the opposite side of the membrane where it is released as oxygen molecule. When water is present in the bio-oil vapor, the process generates in situ hydrogen to facilitate deoxygenation over the electrode that functions as catalyst.