Location: Renewable Product Technology Research2013 Annual Report
1a. Objectives (from AD-416):
The broad goal of this project is to improve the biochemical processes for converting agricultural materials to fuels and chemicals, which will consequently enable cost reductions and increase profitability of biorefining. Research will focus on significant technical challenges that must be overcome to achieve cost-competitive conversion of agricultural feedstocks to biofuels. Objective 1: Develop commercially-viable technologies based on novel deconstruction enzymes for hydrolyzing ligno-cellulose. Objective 2: Develop, via genetic engineering, strains of pentose-utilizing gram-positive bacteria that enable commercially-viable processes for producing fuel-grade ethanol or butanol from ligno-cellulosic hydrolyzates. Objective 3: Develop commercially-preferred methods for preventing, detecting, controlling, and/or correcting economically-harmful microbial contamination in ethanol production facilities. Objective 4: Develop, via high-throughput methods, enzyme and/or microbial-based technologies that enable new commercially-viable coproducts from ethanol fermentations.
1b. Approach (from AD-416):
The growth and sustainability of bioenergy production in the United States (U.S.) are hindered by a number of technical and commercial barriers. Biochemical conversion of lignocellulosic biomass to fuels and chemicals is technically feasible, but inefficiencies in the process make it economically impractical. Accomplishing the objectives will help overcome significant technical challenges to producing sustainable fuels and chemicals from agricultural feedstocks.
3. Progress Report:
Research focuses on four objectives: 1. Develop novel deconstruction enzymes for hydrolyzing lignocellulose; 2. Develop gram-positive bacteria for producing biofuels from lignocellulosic hydrolysates; 3. Develop methods for controlling bacterial contamination of fuel ethanol fermentations; 4. Develop technologies to enable new coproducts from biofuel production. In FY13, ARS Renewable Product Technology Research Unit scientists at the National Center for Agricultural Utilization Research, Peoria, Illinois, made significant progress toward the objectives of this research project, as demonstrated by the following activities: • A bacterial ferulate esterase, an auxiliary enzyme used in deconstructing lignocellulosic biomass, was isolated and its gene (faeA) was cloned and functionally expressed in Escherichia coli. • Novel sources of the enzyme laccase were identified. • Proteins that help confer tolerance to high concentrations of ethanol were identified from the bacterium Lactobacillus buchneri NRRL B-30929. • Bacterial contaminants from commercial fuel ethanol fermentations were screened for impact on yeast utilization of glucose and production of ethanol. • Novel inhibitory agents were tested for their ability to prevent biofilm formation of lactic acid bacteria that contaminate commercial fuel ethanol facilities. • Genes encoding antibacterial enzymes with activity against lactic acid bacteria were expressed in yeast during ethanol fermentation. • Conditions were optimized for the scale-up of schizophyllan production from agricultural biomass in controlled bioreactors. • Strains of Kluyveromyces marxianus were used to produce ethanol from lignocellulosic byproducts of coffee production. • Produced an artificial yeast minichromosome for stable expression of xylose isomerase and xylulokinase genes in fuel ethanol yeast. Progress achieved during FY13 has potential scientific impact for researchers in industry, government, and academia, and will facilitate development and improvement of efficient processes that lower the production costs of fuels and chemicals from renewable agricultural materials.
Rastogi, G., Gurram, R.N., Bhalla, A., Gonzalez, R., Bischoff, K.M., Hughes, S.R., Kumar, S., Sani, R.K. 2013. Presence of glucose, xylose, and glycerol fermenting bacteria in the deep biosphere of the former Homestake gold mine, South Dakota. Frontiers in Microbiology. 4(2):1-8.