Optimization of 1,3-propanediol production from fermentation of crude glycerol by immobilized Bacillus pumilus
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SUBMITTER: Pinyaphong P
PROVIDER: S-EPMC11336579 | biostudies-literature | 2024 Jul
REPOSITORIES: biostudies-literature
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Project description:BackgroundAs the production of biofuels from raw materials continuously increases, optimization of production processes is necessary. A very important issue is the development of wasteless methods of biodiesel production. One way of utilization of glycerol generated in biodiesel production is its microbial conversion to 1,3-PD (1,3-propanediol).ResultsThe study investigated the scale-up of 1,3-PD synthesis from crude glycerol by Clostridium butyricum. Batch fermentations were carried out in 6.6 L, 42 L and 150 L bioreactors. It was observed that cultivation of C. butyricum on a pilot scale did not decrease the efficiency of 1,3-PD production. The highest concentrations of 1,3-PD, 37 g/L for batch fermentation and 71 g/L for fed-batch fermentation, were obtained in the 6.6 L bioreactor. The kinetic parameters of 1,3-PD synthesis from crude glycerol established for batch fermentation were similar regarding all three bioreactor capacities. During fed-batch fermentation, the concentration of 1,3-PD in the 150 L bioreactor was lower and the substrate was not completely utilized. That suggested the presence of multifunctional environmental stresses in the 150 L bioreactor, which was confirmed by protein analysis.ConclusionThe values of effectivity parameters for 1,3-PD synthesis in batch fermentations carried out in 6.6 L, 42 L and 150 L bioreactors were similar. The parameters obtained during fed-batch fermentations in the 150 L bioreactor differed in the rate and percentage of substrate utilization. The analysis of cell proteins demonstrated that a number of multifunctional stresses occurred during fed-batch fermentations in the 150 L bioreactor, which suggests the possibility of identifying the key stages in the biochemical process where inhibition of 1,3-PD synthesis pathways can be observed.
| S-EPMC3974118 | biostudies-literature
Project description:BackgroundThe extracellular xylanase secreted by microorganisms is a hydrolytic enzyme, which arbitrarily cleaves the β-1, 4 backbone of the polysaccharide xylan; an enzyme used in the food processing, bio-pulping and bio-bleaching. The commercial production of the xylanase is limited because of a higher cost involvement, which can be overcome by the cost-effective production of the xylanase through immobilization of the microbial cell by the non-toxic substances.ObjectivesIn this work, the optimization of the extra-cellular cellulase free xylanase production by the immobilized cell of the Bacillus pumilus IMAU80221 strain using Ca-alginate beads along with standardization of the various parameters for a higher xylanase production were studied.Materials and methodsFollowing to sterilization, the Na-alginate solution was mixed with the bacterial suspension of the Bacillus pumilus IMAU80221 and was added drop by drop into the 1 M calcium chloride solution for 1 h for obtaining a uniform sized polymeric bead of the Ca-alginate. For xylanase production, the Ca-alginate beads were then transferred into 100 mL Erlenmeyer flasks with 20 mL of the culture medium containing (w/v) 0.02% NaCl, 0.02% MgSO4, 0.04% (KH4)2PO4, 0.1% peptone, and 0.5% xylan and incubated at 34 °C in an incubator shaker (150 rpm) for 24 h. The resultant supernatant (crude enzyme) was used for enzyme assay.ResultsThe maximum xylanase production by the free cell (1.9 U.mL-1.min-1) was recorded at 48 h which was 40.5% lower than the xylanase production by the immobilized cell (2.67 U.mL-1.min-1) at the same time. The beads containing the immobilized cells could be reused up to eight fermentation cycles for xylanase production and retained 83.5% of the productivity at the fourth cycle. The entrapped cells were stable after six months of storage at 4 °C and retained 68% of the xylanase productivity.ConclusionCellulase free xylanase production from the immobilized Bacillus pumilus IMAU80221 was optimized. The xylanase production by the immobilized cells of Bacillus pumilus was higher by 40.5 and 132.6 % over the free cells respectively after 48 and 72 h of the incubation.
| S-EPMC6697833 | biostudies-literature
Project description:BackgroundGlycerol is currently an over-produced chemical that can be used as substrate for the production of high value products such as 1,3-propanediol (1,3-PDO) in fermentation processes. The aim of this study was to investigate the effect of initial pH on a batch mixed culture fermentation of glycerol, considering both the bacterial community composition and the fermentation patterns.ResultsFor pH values between 5 and 9, 1,3-PDO production yields ranged from 0.52 ± 0.01 to 0.64 ± 0.00 [Formula: see text], with the highest values obtained at pH 7 and 8. An Enterobacteriaceae member closely related to Citrobacter freundii was strongly enriched at all pH values. Within the less dominant bacterial species, two different microbial community structures were found, one at acid pH values and another at neutral to basic pH values.Conclusions1,3-PDO production was improved at pH values over 7. It was anti-correlated with lactate and ethanol production but positively correlated with acetate production. No direct correlation between 1,3-PDO production and a specific family of bacteria was found, suggesting functional redundancies in the microbial community. However, 1,3-PDO production yield remained high over the range of pH studied and was comparable to the best obtained in the same conditions in the literature.
| S-EPMC4744455 | biostudies-literature
Project description:A coccal bacterium (strain ES5) was isolated from methanogenic bioreactor sludge with glycerol as the sole energy and carbon source. Strain ES5 fermented glycerol to 1,3-propanediol as main product, and lactate, acetate and formate as minor products. The strain was phylogenetically closely related to Trichococcus flocculiformis; the rRNA gene sequence similarity was 99%. However, strain ES5 does not show the typical growth in chains of T.?flocculiformis. Moreover, T.?flocculiformis does not ferment glycerol. Strain ES5 used a variety of sugars for growth. With these substrates, lactate, acetate and formate were the main products, while 1,3-propanediol was not formed. The optimum growth temperature of strain ES5 ranges from 30-37°C, but like several other Trichoccoccus strains, strain ES5 is able to grow at low temperature (<?10°C). Therefore, strain ES5 may be an appropriate catalyst for the biotechnological production of 1,3-propanediol from glycerol at low ambient temperature.
| S-EPMC3815333 | biostudies-literature
Project description:Anaerobic fermentation using lignocellulosic hydrolysates as co-substrates is an economically attractive method to enhance 1,3-propanediol (1,3-PD) production by increasing the conversion yield from glycerol. Lignocellulosic hydrolysates contain the mixed sugars that are primarily glucose, xylose, and arabinose. Therefore, these three individual sugars were used, separately, as co-substrates with glycerol, in 1,3-PD production by a Clostridium diolis strain DSM 15410, resulting in an 18%-28% increase in the 1,3-PD yield. Co-fermentation of the mixed sugars and glycerol obtained a higher intracellular NADH/NAD(+) ratio and increased the 1,3-PD yield by 22% relative to fermentation of glycerol alone. Thereafter, two kinds of lignocellulosic hydrolysates, corn stover hydrolysate and corncob molasses, were individually co-fermented with glycerol. The maximum 1,3-PD yield from glycerol reached 0.85 mol/mol. Fed-batch co-fermentation was also performed, improving the 1,3-PD yield (from 0.62 mol/mol to 0.82 mol/mol). These results demonstrate that the co-fermentation strategy is an efficient and economical way to produce 1,3-PD from glycerol.
| S-EPMC4707465 | biostudies-literature
Project description:BackgroundGlycerol is a major byproduct of the biodiesel industry and can be converted to 1,3-propanediol (1,3-PDO) by microorganisms through a two-step enzymatic reaction. The production of 1,3-PDO from glycerol using microorganisms is accompanied by formation of unwanted byproducts, including lactate and 2,3-butanediol, resulting in a low-conversion yield.ResultsKlebsiella pneumoniae was metabolically engineered to produce high-molar yield of 1,3-PDO from glycerol. First, the pathway genes for byproduct formation were deleted in K. pneumoniae. Then, glycerol assimilation pathways were eliminated and mannitol was co-fed to the medium. Finally, transcriptional regulation of the dha operon were genetically modified for enhancing 1,3-propanediol production. The batch fermentation of the engineered strain with co-feeding of a small amount of mannitol yielded 0.76 mol 1,3-PDO from 1 mol glycerol.ConclusionsKlebsiella pneumoniae is useful microorganism for producing 1,3-PDO from glycerol. Implemented engineering in this study successfully improved 1,3-PDO production yield, which is significantly higher than those reported in previous studies.
| S-EPMC5890353 | biostudies-literature
Project description:1,3-propanediol (1,3-PD) is a bulk chemical with myriad applications in polymers, lubricants, cosmetics, foods industries and in the synthesis of heterocyclic compounds. Current commercial production of 1,3-PD involves a thermocatalytic process using acrolein (DuPont) and ethylene oxide (Shell) as starting feedstock. These feedstocks are petroleum-based and there are many efforts at using glycerol as low cost biomass-derived feedstock for 1,3-PD production. A number of catalyst designs and bacterial & fungal strains are being explored for respective catalytic and fermentation routes to glycerol-to-1,3-PD. However, the electrochemical method received little attention for the purpose. In this work, in order to explore the possibility of using partly refined glycerol byproduct of biodiesel production as feedstock, we investigated conversion and 1,3-PD selectivity of glycerol electrolysis in chloride media. We demonstrated selective glycerol-to-1,3-PD conversion using Pt or RuO2-based dsa as anode and Zn or Pb as cathode in NaCl and KCl at pH 1. This electrochemical glycerol-to-1,3-PD conversion is not only green, it is a potential process network loop between biodiesel production and chlor-alkali industry.
| S-EPMC9078992 | biostudies-literature
Project description:Most biosurfactants are obtained using costly culture media and purification processes, which limits their wider industrial use. Sustainability of their production processes can be achieved, in part, by using cheap substrates found among agricultural and food wastes or byproducts. In the present study, crude glycerol, a raw material obtained from several industrial processes, was evaluated as a potential low-cost carbon source to reduce the costs of surfactin production by Bacillus subtilis #309. The culture medium containing soap-derived waste glycerol led to the best surfactin production, reaching about 2.8 g/L. To the best of our knowledge, this is the first report describing surfactin production by B. subtilis using stearin and soap wastes as carbon sources. A complete chemical characterization of surfactin analogs produced from the different waste glycerol samples was performed by liquid chromatography-mass spectrometry (LC-MS) and Fourier transform infrared spectroscopy (FTIR). Furthermore, the surfactin produced in the study exhibited good stability in a wide range of pH, salinity and temperatures, suggesting its potential for several applications in biotechnology.
| S-EPMC8230125 | biostudies-literature
Project description:Crude glycerol is largely generated as the main by-product of the biodiesel industry and is unprofitable for industrial application without costly purification. The direct bioconversion of crude glycerol into 1,3-propanediol (1,3-PDO) by microorganisms is a promising alternative for effective and economic utilization. In this study, Klebsiella pneumoniae 2e was newly isolated for the conversion of crude glycerol into 1,3-PDO. Batch fermentation analysis confirmed that crude glycerol and its main impurities had slight impacts on the growth, key enzyme activity, and 1,3-PDO production of K. pneumoniae 2e. The 1,3-PDO yield from crude glycerol by K. pneumoniae 2e reached 0.64 mol 1,3-PDO/mol glycerol, which was higher than that by most reported 1,3-PDO-producing Klebsiella strains. Genomic profiling revealed that K. pneumoniae 2e possesses 30 genes involved in glycerol anaerobic metabolism and 1,3-PDO biosynthesis. Quantitative real-time PCR analysis of these genes showed that the majority of the genes encoding the key enzymes for glycerol metabolism and 1,3-PDO biosynthesis were significantly upregulated during culture in crude glycerol relative to that in pure glycerol. Further comparative genomic analysis revealed a novel glycerol uptake facilitator protein in K. pneumoniae 2e and a higher number of stress response proteins than in other Klebsiella strains. This work confirms the adaptability of a newly isolated 1,3-PDO-producing strain, K. pneumoniae 2e, to crude glycerol and provides insights into the molecular mechanisms involved in its crude glycerol tolerance, which is valuable for industrial 1,3-PDO production from crude glycerol.IMPORTANCE The rapid development of the biodiesel industry has led to tremendous crude glycerol generation. Due to the presence of complex impurities, crude glycerol has low value for industry without costly purification. Obtaining novel microorganisms capable of direct and efficient bioconversion of crude glycerol to value-added products has great economic potential for industrial application. In this work, we characterized a newly isolated strain, Klebsiella pneumoniae 2e, with the capacity to efficiently produce 1,3-propanediol (1,3-PDO) from crude glycerol and demonstrated its adaptation to crude glycerol. Our work provides insights into the molecular mechanisms of K. pneumoniae 2e adaptation to crude glycerol and the expression patterns of its genes involved in 1,3-PDO biosynthesis, which will contribute to the development of industrial 1,3-PDO production from crude glycerol.
| S-EPMC6498164 | biostudies-literature
Project description:The evolution of the bacterial community in an up-flow anaerobic reactor with silicone support, continuously fed with pure glycerol (day 0-293) and crude glycerol (day 294-362), was studied. Biomass from a former glycerol-degrading reactor was used as inoculum. The maximum yield and productivity of 1,3-propanediol (PDO) (0.62 mol.mol-gly-1 and 14.7 g.L-1.d-1, respectively) were obtained with crude glycerol. The inoculum had low diversity, with dominance of Lactobacillus (70.6%) and Klebsiella/Raoultella (23.3%). After 293 days of feeding with pure glycerol, the abundance of both taxa decreased to less than 10%, either in the attached biofilm or in the biomass growing in suspension. The genus Clostridium and members of the Ruminococcaceae family then became the majority. In the period after feeding with crude glycerol, Clostridium remained as the majority genus in the biofilm; however, it was partially replaced in the suspension by Eubacterium, a non-glycerol degrading bacterium. This fact, together with the prevalence of other glycerol-degrading genera in the biofilm, such as Caproiciproducens and Lactobacillus, indicated that the bacteria attached to the silicone support were responsible for converting glycerol into 1,3-PDO. Therefore, to increase the 1,3-PDO productivity, a good approach would be to maximize the amount of reactor support. Other genera that do not degrade glycerol, such as Anaerobacter and Acetomaculum, thrived at the expense of cellular decay material. The Canonical Correspondence Analysis demonstrated that the origin of glycerol is an important variable to consider during the bioreactor operation for producing 1,3-PDO, while the glycerol loading rate is not. KEY POINTS: • Microbial community showed robustness in a range of operational conditions. • A significantly high 1,3-propanediol yield can be achieved using crude glycerol. • The attached biofilm appears to be key to the high production of 1,3-propanediol.
| S-EPMC11787190 | biostudies-literature