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Yeast cells are transformed with an exogenous xylose isomerase gene. Additional genetic modifications enhance the ability of the transformed cells to ferment xylose to ethanol or other desired fermentation products. Those modifications include deletion of non-specific aldose reductase gene(s), deletion of xylitol dehydrogenase gene(s) and/or overexpression of xylulokinase.
The invention relates to increasing the availability of fermentable sugars from plant biomass, such as glucose and xylose. As described herein, .alpha.-xylosidases can be employed with cellulases to enhance biomass conversion into free, fermentable sugar residues.
Yeast cells are transformed with an exogenous xylose isomerase gene. Additional genetic modifications enhance the ability of the transformed cells to ferment xylose to ethanol or other desired fermentation products. Those modifications include deletion of non-specific or specific aldose reductase gene(s), deletion of xylitol dehydrogenase gene(s) and/or overexpression of xylulokinase.
Termites have specialized digestive systems that overcome the lignin barrier in wood to release fermentable simple sugars. Using the termite Reticulitermes flavipes and its gut symbionts, high-throughput titanium pyrosequencing and proteomics approaches experimentally compared the effects of lignin-containing diets on host-symbiont digestome composition. Proteomic investigations and functional digestive studies with recombinant lignocellulases conducted in parallel provided strong evidence of congruence at the transcription and translational levels and provide enzymatic strategies for overcoming recalcitrant lignin barriers in biofuel feedstocks. Briefly described, therefore, the disclosure provides a system for generating a fermentable product from a lignified plant material, the system comprising a cooperating series of at least two catalytically active polypeptides, where said catalytically active polypeptides are selected from the group consisting of: cellulase Cell-1, $\beta$-glu cellulase, an aldo-keto-reductase, a catalase, a laccase, and an endo-xylanase.
Yeast cells are transformed with an exogenous xylose isomerase gene. Additional genetic modifications enhance the ability of the transformed cells to ferment xylose to ethanol or other desired fermentation products. Those modifications include deletion of non-specific or specific aldose reductase gene(s), deletion of xylitol dehydrogenase gene(s) and/or overexpression of xylulokinase.
The present invention generally relates to processes for recovery of values from a fermentation mass obtained in producing ethanol. Further, the present invention relates to processes for the recovery of values from an inorganic- and lignin-containing mass. The present invention also relates to processes for the recovery of a fraction having enhanced silica content from a silica-containing mass. Still further, the present invention relates to processes for the recovery of crude ethanol from a fermentation mass. The present invention relates to various lignin-containing products and solutions and mineral-rich products.
The present invention provides for a method of fermenting or saccharifying a biomass comprising: (a) (i) contacting a biomass comprising a polysaccharide, and an ionic liquid (IL) to form a first solution, or (ii) providing the first solution comprising the biomass and the IL, (b) contacting the first solution and carbon dioxide such that the first solution results in a lower pH, (c) introducing (i) an enzyme capable of enzymatically to breakdown at least one bond in the polysaccharide or a breakdown product of the polysaccharide, and/or (ii) a microorganism that capable of producing the enzyme and/or fermenting the polysaccharide or a breakdown product of the polysaccharide, such that the polysaccharide is at least partially broken down and the first solution is transformed into a second solution.
The present invention relates to materials and methods for the production of ethanol. More particularly, the present invention provides genetically modified strains of Saccharomyces cerevisiae exhibiting decreased level of BCY1 protein activity and capable of anaerobic fermentation of xylose into ethanol without the need for cell growth. Also provided are methods of using such genetically engineered yeast strains for improved anaerobic xylose fermentation in the yeast for industrial-scale production of various fuels, chemical feedstocks, and synthetic polymers.
The overall objective of this project is to develop a carbon-neutral, microbial dark fermentation technology to convert waste lignocellulosic biomass into H2 with a production cost less than $2/kg-H2 via strain engineering, bioprocess design for scale-up, and integrating fermentation with microbial electrolysis cell (MEC).
The overall objective of this project is to develop a carbon-neutral, microbial dark fermentation technology to convert waste lignocellulosic biomass into H2 with a production cost less than $2/kg-H2 via strain engineering, bioprocess design for scale-up, and integrating fermentation with microbial electrolysis cell (MEC).
The present invention provides for a method of fermenting or saccharifying a biomass comprising: (a) (i) contacting a biomass comprising a polysaccharide, and an ionic liquid (IL) to form a first solution, or (ii) providing the first solution comprising the biomass and the IL, (b) contacting the first solution and carbon dioxide such that the first solution results in a lower pH, (c) introducing (i) an enzyme capable of enzymatically to breakdown at least one bond in the polysaccharide or a breakdown product of the polysaccharide, and/or (ii) a microorganism that capable of producing the enzyme and/or fermenting the polysaccharide or a breakdown product of the polysaccharide, such that the polysaccharide is at least partially broken down and the first solution is transformed into a second solution.
Biomanufacturing can provide on-demand production of mission-critical compounds and materials to support long-duration space exploration while circumventing the challenges of transporting materials from Earth. Synthetic Biology Project is developing two biomanufacturing capabilities: BioNutrients and CO2-Based Manufacturing. BioNutrients is an ongoing mission aboard the International Space Station focused on the production of perishable nutrients in an on demand for direct for consumption. The first flight experiment of this project targeted the production of carotenoids: β-carotene and zeaxanthin, in recombinant yeast strains. Since then, the project has expanded to encompass the production of the fermented consumables like yogurt and kefir for use as a nutrient delivery mechanism. The CO2-Based Manufacturing system aims to use in situ resources to allow for biomanufacturing with minimal re-supply required. The manufacturing platform is combined with an electrochemical CO2 conversion system which can produce simple carbon substrates to support microbial based biomanufacturing. A comprehensive ground-based platform for recombinant protein purification is in development with the goal of producing a thermostable carbonic anhydrase enzyme from E. coli utilizing CO2-derived acetate. Our group hopes to propel advancements in space biomanufacturing for long duration space flight by harnessing the tools of synthetic biology.
Clostridium ljungdahlii was grown on syngas of varying composition to investigate how syngas blends used in fermentation can be tailored toward desired product formation. Experiments were conducted with liquid batch cultures exposed to the same volume of gas with varying ratios of hydrogen to carbon monoxide (H 2 /CO). Formation of acetate was favored by higher concentrations of hydrogen in the headspace. The maximum acetate concentration of 35.21 +/- 0.84 mM was obtained using an H 2 /CO ratio of 2.0. Generation of more reduced metabolites was favored by greater carbon monoxide concentrations in the headspace. Maximum ethanol (7.53 +/- 0.58 mM) and 2,3-Butanediol (5.20 +/- 0.79 mM) concentrations were achieved under an H 2 /CO ratio of 0.5. Linear relationships were obtained in that describe the effect of the syngas H 2 /CO ratios on acetate, ethanol, and 2,3-BD formation, respectively.
Miscanthus × giganteus (Mxg) is a warm-season perennial grass being commercialized as a biomass feedstock for temperate farms. Three process strategies were compared for converting Mxg into single-cell oil and extracted lignin intermediates, as hydrothermal (HT) processing and two natural deep eutectic solvents (NADES), ChCl:LA (choline chloride:lactic acid) and ChCl:Gly (choline chloride:glycerol). Pretreatments were performed at 10% and 50% solids loading at 140 °C, 2 h; HT: 190 °C, 10 min. Enzymatic hydrolysates, generated at 10% solids using washed and unwashed biomass, were evaluated for microbial lipid production. Maximum glucose conversions from washed biomass reached 83.5% (ChCl:LA), 52.7% (ChCl:Gly), and 74.0% (HT). Remarkably, NADES-derived hydrolysates effectively replaced refined sugars for the cultivation of the oleaginous yeast Rhodotorula toruloides, achieving ∼51% higher biomass (OD 90.7) and lipid titers of 19.36 g/L within 45 h using a two-stage fermentation strategy. Lipid contents ranged from 34.5–44.5% dry weight, demonstrating reduced reliance on purified sugars. Beyond carbohydrate valorization, ChCl:LA pretreatment enabled high-purity lignin recovery (>89%) in a lignin-first strategy. Structural analyses (2D-HSQC and ³¹P NMR) showed syringyl (78.15%), guaiacyl (15.15%), and p-hydroxyphenyl (6.41%) units, with higher phenolic hydroxyl content (0.91 mmol/g) and a lower S/G ratio (0.19) than HT lignin (0.87 mmol/g, S/G 0.22). These attributes favor downstream lignin depolymerization into low-molecular-weight aromatics. Overall, NADES pretreatment simultaneously enhances microbial lipid yields and recovers high-quality lignin, advancing the economic feasibility of renewable diesel and sustainable aviation fuel (SAF) production from bioenergy crops within an integrated biorefinery framework.
In this study we demonstrated the technical feasibility of a prolonged, sequential two-stage integrated process under a repeated batch mode of starch fermentation. In this durable scheme, the photobioreactor with purple bacteria in the second stage was fed directly with dark culture from the first stage without centrifugation, filtration, or sterilization (not demonstrated previously). After preliminary optimization, both the dark- and the photo-stages were performed under repeated batch modes with different process parameters. Continuous H{sub 2} production in this system was observed at a H{sub 2} yield of up to 1.4 and 3.9 mole mole{sup -1} hexose during the dark- and photo-stage, respectively (for a total of 5.3 mole mole{sup -1} hexose), and rates of 0.9 and 0.5 L L{sup -1} d{sup -1}, respectively. Prolonged repeated batch H{sub 2} production was maintained for up to 90 days in each stage and was rather stable under non-aseptic conditions. Potential for improvements in these results are discussed.
Highlights: • Bacillus thuringiensis (Bt) growth on non-sterile OFMSW has been demonstrated. • Bt-enriched compost can be produced from non-sterile biowaste. • Non-sterile OFMSW can be valorized through semi-continuous SSF and Bt inoculation. • The self-sustained inoculation procedure proposed will enhance process economics. - Abstract: In the framework of a circular economy, organic solid wastes are considered to be resources useful for obtaining value-added products. Among other potential uses, biodegradable wastes from agricultural, industrial, and domestic sources are being studied to obtain biopesticides through solid-state fermentation (SSF), mainly at the laboratory scale. The suitability of biowaste (source-selected organic fraction of municipal solid waste) for use as a substrate for Bacillus thuringiensis (Bt) growth under non-sterile conditions in a 10 L SSF reactor was determined in this study. An operational strategy for setting up a semi-continuous process yielding a stabilised organic compost-like material enriched with Bt suitable for use as a soil amendment was developed. Concentrations of 1.7·10{sup 7}–2.2·10{sup 7} and 1.3·10{sup 7}–2.1·10{sup 7} CFU g{sup −1} DM for Bt viable cells and spores, respectively, were obtained in the final material. As the results confirmed, Bt-enriched compost-like material with potential biopesticide properties can be produced from non-sterile biowaste.
This research investigates the bed agglomeration phenomena during the steam gasification of a high lignin residue produced from the simultaneous saccharification and fermentation (SSF) of corn stover in a bubbling fluidized bed. The studies were conducted at 895°C using alumina as bed material. Biomass was fed at 1.5 kg/hr, while steam was fed to give a velocity equal to 2.5 times the minimum fluidization velocity, with a steam/carbon ratio of 0.9. The pelletized feedstock was co-fed with a cooling nitrogen stream to mitigate feed line plugging issues. Tar production was high at 50.3 g/Nm3, and the fraction of C10+ compounds was greater than that seen in the gasification of traditional lignocellulosic feedstocks. Carbon closures over 94 % were achieved for all experiments. Bed agglomeration was found to be problematic, indicated by pressure drop increases observed below the bed and upstream of the feed line. Two size categories of solids were recovered from the reactor, +60 mesh and -60 mesh. After a 2.75-hour experiment, 61.7 wt % was recovered as -60 mesh particles and 38.2 wt% of the recovered reactor solids were +60 mesh. A sizeable percentage, 31.8 wt%, was +20 mesh. The -60 mesh particles were mainly formed by the initial bed material (Al2O3). Almost 50 wt. % of the + 20 mesh particles was found to be formed by organics. The unreacted carbon remaining in the reactor resulted in a low conversion rate to product gas. ICP-AES, SEM, SEM-EDS, and XRD confirmed that the large agglomerates (+ 20 mesh) were not encapsulated bed material but rather un-gasified feedstock pellets with sand particles attached to it.
In this paper, the stochastic growth logistic model with aftereffect for the cell growth of C. acetobutylicum P262 and Luedeking-Piret equations for solvent production in batch fermentation system is introduced. The parameters values of the mathematical models are estimated via Levenberg-Marquardt optimization method of non-linear least squares. We apply Milstein scheme for solving the stochastic models numerically. The effciency of mathematical models is measured by comparing the simulated result and the experimental data of the microbial growth and solvent production in batch system. Low values of Root Mean-Square Error (RMSE) of stochastic models with aftereffect indicate good fits.