Highly efficient production of transfructosylating enzymes using low-cost sugarcane molasses by A. pullulans FRR 5284
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ABSTRACT:
SUBMITTER: Khatun M
PROVIDER: S-EPMC10992317 | biostudies-literature | 2021 Jun
REPOSITORIES: biostudies-literature
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Project description:BackgroundPolymalic acid (PMA) is a water-soluble biopolymer with many attractive properties for food and pharmaceutical applications mainly produced by the yeast-like fungus Aureobasidium pullulans. Acid hydrolysis of PMA, resulting in release of the monomer l-malic acid (MA), which is widely used in the food and chemical industry, is a competitive process for producing bio-based platform chemicals.ResultsIn this study, the production of PMA and MA from sucrose and sugarcane molasses by A. pullulans was studied in shake flasks and bioreactors. Comparative metabolome analysis of sucrose- and glucose-based fermentation identified 81 intracellular metabolites and demonstrated that pyruvate from the glycolysis pathway may be a key metabolite affecting PMA synthesis. In silico simulation of a genome-scale metabolic model (iZX637) further verified that pyruvate carboxylase (pyc) via the reductive tricarboxylic acid cycle strengthened carbon flux for PMA synthesis. Therefore, an engineered strain, FJ-PYC, was constructed by overexpressing the pyc gene, which increased the PMA titer by 15.1% compared with that from the wild-type strain in a 5-L stirred-tank fermentor. Sugarcane molasses can be used as an economical substrate without any pretreatment or nutrient supplementation. Using fed-batch fermentation of FJ-PYC, we obtained the highest PMA titers (81.5, 94.2 g/L of MA after hydrolysis) in 140 h with a corresponding MA yield of 0.62 g/g and productivity of 0.67 g/L h.ConclusionsWe showed that integrated metabolome- and genome-scale model analyses were an effective approach for engineering the metabolic node for PMA synthesis, and also developed an economical and green process for PMA and MA production from renewable biomass feedstocks.
| S-EPMC5883625 | biostudies-literature
Project description:BackgroundGinsenosides are Panax plant-derived triterpenoid with wide applications in cardiovascular protection and immunity-boosting. However, the saponins content of Panax plants is fairly low, making it time-consuming and unsustainable by direct extraction. Protopanaxadiol (PPD) is a common precursor of dammarane-type saponins, and its sufficient supply is necessary for the efficient synthesis of ginsenoside.ResultsIn this study, a combinational strategy was used for the construction of an efficient yeast cell factory for PPD production. Firstly, a PPD-producing strain was successfully constructed by modular engineering in Saccharomyces cerevisiae BY4742 at the multi-copy sites. Then, the INO2 gene, encoding a transcriptional activator of the phospholipid biosynthesis, was fine-tuned to promote the endoplasmic reticulum (ER) proliferation and improve the catalytic efficiency of ER-localized enzymes. To increase the metabolic flux of PPD, dynamic control, based on a carbon-source regulated promoter PHXT1, was introduced to repress the competition of sterols. Furthermore, the global transcription factor UPC2-1 was introduced to sterol homeostasis and up-regulate the MVA pathway, and the resulting strain BY-V achieved a PPD production of 78.13 ± 0.38 mg/g DCW (563.60 ± 1.65 mg/L). Finally, sugarcane molasses was used as an inexpensive substrate for the first time in PPD synthesis. The PPD titers reached 1.55 ± 0.02 and 15.88 ± 0.65 g/L in shake flasks and a 5-L bioreactor, respectively. To the best of our knowledge, these results were new records on PPD production.ConclusionThe high-level of PPD production in this study and the successful comprehensive utilization of low-cost carbon source -sugarcane molassesindicate that the constructed yeast cell factory is an excellent candidate strain for the production of high-value-added PPD and its derivativeswith great industrial potential.
| S-EPMC9636795 | biostudies-literature
Project description: Not available
| S-EPMC10992603 | biostudies-literature
Project description:Toxic substance usage remains one of the major concerns that must be addressed toward the commercialization of perovskite photovoltaics. Herein, we report a highly efficient perovskite solar module (>13%) fabricated via a wet process that uses a unique aqueous Pb(NO3)2 precursor, eliminating the use of toxic organic solvents during perovskite film preparation. In addition, we demonstrate a unique pattern in a monolithically interconnected module structure to check the uniformity of perovskite film and the quality of laser scribing. Finally, we highlight that this aqueous Pb(NO3)2 precursor protocol could achieve an enormous cost reduction over conventional PbI2 organic solutions whether in the laboratory research stage or at mass production scale, strengthening the core competitiveness of perovskite solar cells in the Darwinian ocean of photovoltaic technologies.
| S-EPMC9655964 | biostudies-literature
Project description:BackgroundDeveloping novel microbial cell factories requires careful testing of candidates under industrially relevant conditions. However, this frequently occurs late during the strain development process. The availability of laboratory media that simulate industrial-like conditions might improve cell factory development, as they allow for strain construction and testing in the laboratory under more relevant conditions. While sugarcane molasses is one of the most important substrates for the production of biofuels and other bioprocess-based commodities, there are no defined media that faithfully simulate it. In this study, we tested the performance of a new synthetic medium simulating sugarcane molasses.ResultsLaboratory scale simulations of the Brazilian ethanol production process, using both sugarcane molasses and our synthetic molasses (SM), demonstrated good reproducibility of the fermentation performance, using yeast strains, PE-2 and Ethanol Red™. After 4 cycles of fermentation, the final ethanol yield (gp gs-1) values for the SM ranged from 0.43 ± 0.01 to 0.44 ± 0.01 and from 0.40 ± 0.01 to 0.46 ± 0.01 for the molasses-based fermentations. The other fermentation parameters (i.e., biomass production, yeast viability, and glycerol and acetic acid yield) were also within similar value ranges for all the fermentations. Sequential pairwise competition experiments, comparing industrial and laboratory yeast strains, demonstrated the impact of the media on strain fitness. After two sequential cocultivations, the relative abundance of the laboratory yeast strain was 5-fold lower in the SM compared to the yeast extract-peptone-dextrose medium, highlighting the importance of the media composition on strain fitness.ConclusionsSimulating industrial conditions at laboratory scale is a key part of the efficient development of novel microbial cell factories. In this study, we have developed a synthetic medium that simulated industrial sugarcane molasses media. We found good agreement between the synthetic medium and the industrial media in terms of the physiological parameters of the industrial-like fermentations.
| S-EPMC6086992 | biostudies-literature
Project description:Pichia veronae strain HSC-22 (accession number KP012558) showed a good tolerance to relatively high temperature, ethanol and sugar concentrations. Response surface optimization based on central composite design of experiments predicted the optimal values of the influencing parameters that affect the production of bioethanol from sugarcane molasses to be as follows: initial pH 5, 25% (w : v) initial molasses concentration, 35°C, 116 rpm, and 60 h. Under these optimum operating conditions the maximum bioethanol production on a batch fermenter scale was recorded as 32.32 g/L with 44% bioethanol yield.
| S-EPMC4687335 | biostudies-literature
Project description: Not available
| S-EPMC11923641 | biostudies-literature
Project description:An RNA enzyme has been developed that catalyzes the joining of oligonucleotide substrates to form additional copies of itself, undergoing self-replication with exponential growth. The enzyme also can cross-replicate with a partner enzyme, resulting in their mutual exponential growth and enabling self-sustained Darwinian evolution. The opportunity for inventive evolution within this synthetic genetic system depends on the diversity of the evolving population, which is limited by the catalytic efficiency of the enzyme. Directed evolution was used to improve the efficiency of the enzyme and increase its exponential growth rate to 0.14 min(-1), corresponding to a doubling time of 5 min. This is close to the limit of 0.21 min(-1) imposed by the rate of product release, but sufficient to enable more than 80 logs of growth per day.
| S-EPMC3943892 | biostudies-literature
Project description:Developing an effective and low-cost system to synthesize titanium silicalite-1 (TS-1) zeolite is desirable for a range of industrial applications. To date, the poor catalytic activity of the synthesized zeolite due to the low amount of framework titanium and large crystal size is the main obstacle limiting the widespread application of this material. Moreover, a large amount of wastewater is often produced by the existing synthesis process. Herein, a green and sustainable route for synthesizing small-crystal TS-1 with a high fraction of framework Ti was demonstrated via a seed-assisted method using a tetrapropylammonium bromide (TPABr)-ethanolamine hydrothermal system. The influence of the synthesis conditions on the physicochemical properties and catalytic activities of TS-1 was investigated. With the assistance of nanosized S-1 seeds, the incorporation of Ti into the framework of TS-1 was promoted, and the crystallization rate was effectively accelerated. After alkaline etching, the obtained hierarchical TS-1 had higher catalytic activity towards propylene epoxidation with an extremely high turnover frequency of 1,650 h-1. Furthermore, the mother liquid during the hydrothermal reaction could be reused for the next synthesis procedure. Consequently, utilization ratios of both ethanolamine and TPABr exceeding 95% were achieved by recycling the mother liquid. This low-cost approach for reducing wastewater could be easily scaled up to provide a promising synthesis method for the industrial production of TS-1 and other topological zeolites.
| S-EPMC8215215 | biostudies-literature
Project description:Lignocellulosic wastes, rice straw, sugarcane bagasse, rice bran and sawdust, and pure commercial carboxymethyl cellulose (CMC) and xylan were used as substrates to cultivate cellulolytic fungus, Aspergillus flavus KUB2, in submerged fermentation at 30°C. Of all the substrates, sugarcane bagasse was a good source for the production of cellulolytic and also hemicellulolytic enzymes. The maximum activities of endoglucanase (CMCase), total cellulase (FPase) and xylanase using sugarcane bagasse as substrate were 8%, 75% and 165%, respectively, higher than those of the commercial substrates. The time course determination of enzyme production revealed that the highest CMCase (1.27 U/ml), FPase (0.72 U/ml) and xylanase (376.81 U/ml) activities were observed at 14 days of fermentation. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) analyses confirmed the efficient structural alteration of sugarcane bagasse caused by enzymatic actions during A. flavus KUB2 cultivation. Based on the results of the hydrolytic enzyme activities, FTIR and SEM, A. flavus KUB2 is suggested as an efficient hydrolytic enzymes producer and an effective lignocellulose degrader, while sugarcane bagasse can be applied as a low-cost carbon source for the economical production of lignocellulose hydrolytic enzymes by A. flavus KUB2.
| S-EPMC8128202 | biostudies-literature