Bioconversion of cellulose into bisabolene using Ruminococcus flavefaciens and Rhodosporidium toruloides

Walls, Laura E.; Otoupal, Peter B.; Ledesma‐Amaro, Rodrigo; Velásquez-Orta, Sharon B.; Gladden, John M.; Rios‐Solis, Leonardo

doi:10.1016/j.biortech.2022.128216

Cited by 16 publications

(14 citation statements)

References 41 publications

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“…However, it is possible that this contamination was actually beneficial for promoting the conversion of lactic acid into acetic acid, a carbon source that R. toruloides appears to prefer. We have recently shown that R. toruloides consumes acetic acid while avoiding succinic acid consumption in a proof-of-concept sequential bioreactor setup, supporting the notion of preferential organic acid consumption by R. toruloides from mixed-carbon feedstocks [48]. Despite this contamination, R. toruloides growth and production of TAL remained robust.…”

Section: One-pot Il Synthesis Pretreatment Saccharification and Biore...supporting

confidence: 52%

Advanced one-pot deconstruction and valorization of lignocellulosic biomass into triacetic acid lactone using Rhodosporidium toruloides

et al. 2022

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Background Rhodosporidium toruloides is capable of co-utilization of complex carbon sources and robust growth from lignocellulosic hydrolysates. This oleaginous yeast is therefore an attractive host for heterologous production of valuable bioproducts at high titers from low-cost, deconstructed biomass in an economically and environmentally sustainable manner. Here we demonstrate this by engineering R. toruloides to produce the polyketide triacetic acid lactone (TAL) directly from unfiltered hydrolysate deconstructed from biomass with minimal unit process operations. Results Introduction of the 2-pyrone synthase gene into R. toruloides enabled the organism to produce 2.4 g/L TAL from simple media or 2.0 g/L from hydrolysate produced from sorghum biomass. Both of these titers are on par with titers from other better-studied microbial hosts after they had been heavily engineered. We next demonstrate that filtered hydrolysates produced from ensiled sorghum are superior to those derived from dried sorghum for TAL production, likely due to the substantial organic acids produced during ensiling. We also demonstrate that the organic acids found in ensiled biomass can be used for direct synthesis of ionic liquids within the biomass pretreatment process, enabling consolidation of unit operations of in-situ ionic liquid synthesis, pretreatment, saccharification, and fermentation into a one-pot, separations-free process. Finally, we demonstrate this consolidation in a 2 L bioreactor using unfiltered hydrolysate, producing 3.9 g/L TAL. Conclusion Many steps involved in deconstructing biomass into fermentable substrate can be combined into a distinct operation, and directly fed to cultures of engineered R. toruloides cultures for subsequent valorization into gram per liter titers of TAL in a cost-effective manner.

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Section: One-pot Il Synthesis Pretreatment Saccharification and Biore...supporting

confidence: 52%

Advanced one-pot deconstruction and valorization of lignocellulosic biomass into triacetic acid lactone using Rhodosporidium toruloides

et al. 2022

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“…However, even if the theoretical yield is achieved, approximately 60 to 70% of starting carbon material is not converted to the desired molecule. While various bench-scale studies (Table A1) reported nearly 100% utilization of carbon sources (Perez-Pimienta et al 2019;Walls et al 2023), it is apparent that the initial carbon that does not go to the desired product will lead to CO2 emissions and the formation of cell mass. Typically, CO2 emission is not measured during microbial strain development at laboratory scale.…”

Section: Introductionmentioning

confidence: 99%

Integration of genome-scale metabolic model with biorefinery process model reveals market-competitive carbon-negative sustainable aviation fuel utilizing microbial cell mass lipids and biogenic CO2

Baral,

Banerjee,

Mukhopadhyay

et al. 2024

BioRes

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Producing scalable, economically viable, low-carbon biofuels or biochemicals hinges on more efficient bioconversion processes. While microbial conversion can offer robust solutions, the native microbial growth process often redirects a large fraction of carbon to CO2 and cell mass. By integrating genome-scale metabolic models with techno-economic and life cycle assessment models, this study analyzes the effects of converting cell mass lipids to hydrocarbon fuels, and CO2 to methanol on the facility’s costs and life-cycle carbon footprint. Results show that upgrading microbial lipids or both microbial lipids and CO2 using renewable hydrogen produces carbon-negative bisabolene. Additionally, on-site electrolytic hydrogen production offers a supply of pure oxygen to use in place of air for bioconversion and fuel combustion in the boiler. To reach cost parity with conventional jet fuel, renewable hydrogen needs to be produced at less than $2.2 to $3.1/kg, with a bisabolene yield of 80% of the theoretical yield, along with cell mass and CO2 yields of 22 wt% and 54 wt%, respectively. The economic combination of cell mass, CO2, and bisabolene yields demonstrated in this study provides practical insights for prioritizing research, selecting suitable hosts, and determining necessary engineered production levels.

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“…These biofuels are produced using aerobic microbial hosts ,, and have a volumetric energy density 38–86% higher than that of ethanol (29.2–39.3 MJ/L for advanced biofuels compared to 21.1 MJ/L for ethanol). , The higher selling price and carbon footprint of advanced biofuels, compared to those of ethanol, are primarily due to a lower bioconversion yield (25–35 wt % from sugars for advanced biofuels , compared to 51 wt % from sugars for ethanol) and the capital and energy-intensive aerobic bioconversion process . Recent bench-scale experiments have demonstrated bisabolene yields of 19.6 g per 100 g of glucose, 2.2 g per 100 g of mixed sugars (glucose, xylose, and arabinose), 7.6 g per 100 g of organic acids, and 0.77 g per 100 g of bone-dry biomass feedstock based on utilization of an ensiled biomass sorghum hydrolysate that included glucose, xylose, and organic acids.…”

Section: Introductionmentioning

confidence: 99%

“…17,22 The higher selling price and carbon footprint of advanced biofuels, compared to those of ethanol, are primarily due to a lower bioconversion yield (25−35 wt % from sugars for advanced biofuels 17,22 compared to 51 wt % from sugars for ethanol 2 ) and the capital and energy-intensive aerobic bioconversion process. 23 Recent bench-scale experiments have demonstrated bisabolene yields of 19.6 g per 100 g of glucose, 24 2.2 g per 100 g of mixed sugars (glucose, xylose, and arabinose), 25 7.6 g per 100 g of organic acids, 26 and 0.77 g per 100 g of bone-dry biomass feedstock 27 based on utilization of an ensiled biomass sorghum hydrolysate that included glucose, xylose, and organic acids. Different microbial hosts, including Escherichia coli, 18 Saccharomyces cerevisiae, 18 and Rhodosporidium toruloides, 20 have been engineered to produce renewable bisabolene primarily using the plant-derived sugars such as glucose and xylose.…”

Section: ■ Introductionmentioning

confidence: 99%

Economic and Environmental Trade-Offs of Simultaneous Sugar and Lignin Utilization for Biobased Fuels and Chemicals

Baral,

Banerjee,

Mukhopadhyay

et al. 2023

ACS Sustainable Chem. Eng.

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Efficient lignin conversion is vital to the production of affordable, low-carbon fuels and chemicals from lignocellulosic biomass. However, lignin conversion remains challenging, and the alternative (combustion) can emit harmful air pollutants. This study explores the economic and environmental trade-offs between lignin combustion and microbial utilization for producing bisabolene as a representative biobased fuel or chemical. Results for switchgrass and clean pine-based biorefineries show that using lignin to increase fuel yields rather than combusting it reduces the capital expenditures for the boiler and turbogenerator if the facilities process more than 1100 bone-dry metric tons (bdt) feedstock/day and 560 bdt/day, respectively. No comparable advantage was observed for lower-lignin sorghum feedstock. Deconstructing lignin to bioavailable intermediates and utilizing those small molecules alongside sugars to boost product yields is economically attractive if the overall lignin-to-product conversion yield exceeds 11–20% by mass. Although lignin-to-fuel/chemical conversion can increase life-cycle greenhouse gas (GHG) emissions, most of the lignin can be diverted to fuel/chemical production while maintaining a >60% life-cycle GHG footprint reduction relative to diesel fuel. The results underscore that lignin utilization can be economically advantageous relative to combustion for higher-lignin feedstocks, but efficient depolymerization and high yields during conversion are both crucial to achieving viability.

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Bioconversion of cellulose into bisabolene using Ruminococcus flavefaciens and Rhodosporidium toruloides

Cited by 16 publications

References 41 publications

Advanced one-pot deconstruction and valorization of lignocellulosic biomass into triacetic acid lactone using Rhodosporidium toruloides

Advanced one-pot deconstruction and valorization of lignocellulosic biomass into triacetic acid lactone using Rhodosporidium toruloides

Integration of genome-scale metabolic model with biorefinery process model reveals market-competitive carbon-negative sustainable aviation fuel utilizing microbial cell mass lipids and biogenic CO2

Economic and Environmental Trade-Offs of Simultaneous Sugar and Lignin Utilization for Biobased Fuels and Chemicals

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