N. V. S. N. Murthy Konda

Transforming biomass conversion with ionic liquids: process intensification and the development of a high-gravity, one-pot process for the production of cellulosic ethanol

Producing concentrated sugars and minimizing water usage are key elements in the economics and environmental sustainability of advanced biofuels. Conventional pretreatment processes that require a water-wash step can result in losses of fermentable sugars and generate large volumes of wastewater or solid waste. To address these problems, we have developed high gravity biomass processing with a one-pot conversion technology that includes ionic liquid pretreatment, enzymatic saccharification, and yeast fermentation for the production of concentrated fermentable sugars and high-titer cellulosic ethanol. The use of dilute bio-derived ionic liquids (a.k.a. bionic liquids) enables one-pot, high-gravity bioethanol production due to their low toxicity to the hydrolytic enzyme mixtures and microbes used. We increased biomass digestibility at >30 wt% loading by understanding the relationship between ionic liquid and biomass loading, yielding 41.1 g L−1 of ethanol (equivalent to an overall yield of 74.8% on glucose basis) using an integrated one-pot fed-batch system. Our technoeconomic analysis indicates that the optimized one-pot configuration provides significant economic and environmental benefits for cellulosic biorefineries by reducing the amount of ionic liquid required by ∼90% and pretreatment-related water inputs and wastewater generation by ∼85%. In turn, these improvements can reduce net electricity use, greenhouse gas-intensive chemical inputs for wastewater treatment, and waste generation. The result is an overall 40% reduction in the cost of cellulosic ethanol produced and a reduction in local burdens on water resources and waste management infrastructure.

An Investigation on the Economic Feasibility of Macroalgae as a Potential Feedstock for Biorefineries

Macroalgal biomass has been considered as a prospective feedstock for biofuel production as, among other benefits, it is an abundant source of renewable sugars and its growth does not require arable land, fresh water, or intense care. Successful commercial deployment of macroalgae-based biorefineries, however, depends on their economic viability at industrial scales. A key objective of this study was to carry out a detailed technoeoconomic analysis (TEA) of a macroalgae biorefinery to understand the economic potential and cost drivers of macroalgae as a feedstock for the production of biofuels and biochemicals. Ethanol was used as a representative macroalgae-derived product, given the wealth of public information available to model this option, and the analysis was extended to biomass-derived sugars in order to explore the production of other fermentation-derived chemicals. Sensitivity analysis was performed on various cost drivers, such as macroalgae price, yield, solids loading, and enzyme loading during hydrolysis. With a feedstock price of

CO2 enabled process integration for the production of cellulosic ethanol using bionic liquids

100/MT, depending on the maturity of the other key process parameters (i.e., yield, solids loading, and enzyme loading), the minimum ethanol selling price (MESP) was observed to be in the range of

One-pot integrated biofuel production using low-cost biocompatible protic ionic liquids

3.6–8.5/gal and reduced to

Switchable ionic liquids based on di-carboxylic acids for one-pot conversion of biomass to an advanced biofuel

2.9–7.5/gal with macroalgae priced at

Efficient dehydration and recovery of ionic liquid after lignocellulosic processing using pervaporation

50/MT. For production of chemicals, sugar prices were in the range of ¢21–47/lb or ¢16–40/lb with macroalgae priced at

Development of an integrated approach for α-pinene recovery and sugar production from loblolly pine using ionic liquids

100/MT and

Simultaneous application of predictive model and least cost formulation can substantially benefit biorefineries outside Corn Belt in United States: A case study in Florida

50/MT, respectively. Given the challenging economics of the macroalgae biorefinery, coproduction of alginate was used to show the importance of multiple revenue sources, though issues regarding market saturation continue to arise when dealing with products of disparate market sizes.

Predictive modeling to de-risk bio-based manufacturing by adapting to variability in lignocellulosic biomass supply

There is a clear and unmet need for a robust and affordable biomass conversion technology that can process a wide range of biomass feedstocks and produce high yields of fermentable sugars and biofuels with minimal intervention between unit operations. The lower microbial toxicity of recently-developed renewable ionic liquids (ILs), or bionic liquids (BILs), helps overcome the challenges associated with the integration of pretreatment with enzymatic saccharification and microbial fermentation. However, the most effective BILs known to date for biomass pretreatment form extremely basic pH solutions in the presence of water, and therefore require neutralization before the pH range is acceptable for the enzymes and microbes used to complete the biomass conversion process. Neutralization using acids creates unwanted secondary effects that are problematic for efficient and cost-effective biorefinery operations using either continuous or batch modes. We demonstrate a novel approach that addresses these challenges through the use of gaseous carbon dioxide to reversibly control the pH mismatch. This approach enables the realization of an integrated biomass conversion process that eliminates the need for intermediate washing and/or separation steps. A preliminary technoeconomic analysis indicates that this integrated approach could reduce production costs by 50–65% compared to previous IL biomass conversion methods studied.

Life-Cycle Greenhouse Gas and Water Intensity of Cellulosic Biofuel Production Using Cholinium Lysinate Ionic Liquid Pretreatment

The transformation of biomass into liquid fuels is of great importance. Previous work has demonstrated the capability of specific ionic liquids (ILs), such as 1-ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]) and cholinium lysinate ([Ch][Lys]), to be effective biomass pretreatment solvents. Using these ILs for an integrated biomass-to-biofuel configuration is still challenging due to a significant water-wash related to the high toxicity of [C2C1Im][OAc] and pH adjustment prior to saccharification for the highly basic [Ch][Lys]. In this work, we demonstrate, for the first time, that a one-pot integrated biofuel production is enabled by a low cost (∼