Dual Carbon Sources Research Articles

Enhancing lithium-storage properties through amino functionalization in two-dimensional lamellar carbon-supported mesoporous SiO2 nanospheres

Currently, common two-dimensional (2D) carbon materials composited with Si-based materials as anode for lithium-ion batteries exhibit excellent electrochemical properties. In this study, we describe the one-step synthesis of amino-functionalized mesoporous silica (SiO2) nanospheres through self-assembly. Morphology modulation and amino group grafting were performed simultaneously without secondary modification. Using tartaric acid and melamine as dual carbon sources, the 2D lamellar structure was constructed using the dehydration condensation reaction, with the mesoporous SiO2 nanospheres uniformly intercalated within the carbon sheets. The composites were securely bonded by chemical bonding, effectively addressing the issue of structural collapse often encountered in silica–carbon composites. Ultimately, the lamellar SiO2@NC composite exhibited stable capacity of 539.5 mAh g−1 after 500 cycles at 1 A g−1. This strategy is simple and effective, compared to the complex processes typically associated with 2D carbon materials synthesis, and can be potentially extended to applications in catalysis, adsorption, and separation within diverse fields.

Carbon-Interconnected Sodium Vanadium Phosphate Microparticles: Material Characterizations and Na+-Storage Performances

Sodium vanadium phosphate (Na3V2(PO4)3) with continuous carbon-coating (NVP/C) has been regarded as one of the most promising cathode materials for sodium-ion batteries (SIBs) owing to the three-dimensional sodium superionic conductor (NASICON) structure for fast sodium-ion migrations, high theoretical energy density (ca. 400 Wh/kg), and good thermal stability (450°C). In this study, carbon-interconnected NVP/C microparticles (C@NVP/C MPs) were successfully synthesized by employing ascorbic acid and sodium-containing polymer as dual carbon sources, followed by calcination at 750°C in an argon atmosphere. The resulting C@NVP/C MPs not only exhibited great crystallinity, high purity, and size of 5-10 μm but also possessed carbon amounts of 9.9 wt. %, as confirmed through the X-ray diffractometer, scanning electron microscope, and thermogravimetric analyzer, respectively. The cyclic voltammogram revealed that the potential difference between oxidation and reduction peaks of C@NVP/C (174 mV at 0.1 mV/sec and 382 mV at 1.0 mV/sec) was less than that of the NVP/C nanoparticles (197 mV at 0.1 mV/sec and 391 mV at 1.0 mV/sec) that were synthesized without adding the sodium-containing polymer. Moreover, the same reversible capacity was delivered from C@NVP/C, i.e., 75 mAh/g at 0.1 C. Those improved electrochemical performances could be attributed to the well-interconnection between NVP/C and carbon originating from the pyrolysis of sodium-containing polymer, creating additional electronic transportation pathways. Accordingly, the C@NVP/C MPs synthesized in the present study are reasonably anticipated to be promising cathode materials for SIBs.

Engineering a versatile yeast platform for sesquiterpene production from glucose or methanol.

Natural sesquiterpene are valuable compounds with diverse applications in industries, such as cosmetics and energy. Microbial synthesis offers a promising way for sesquiterpene production. Methanol, can be synthesized from CO2 and solar energy, serves as a sustainable carbon source. However, it is still a challenge to utilize methanol for the synthesis of value-added compounds. Pichia pastoris (syn. Komagataella phaffii), known for its efficient utilization of glucose and methanol, has been widely used in protein synthesis. With advancements in technology, P. pastoris is gradually engineered for chemicals production. Here, we successfully achieved the synthesis of α-bisabolene in P. pastoris with dual carbon sources by expressing the α-bisabolene synthase gene under constitutive promoters. We systematically analyzed the effects of different steps in the mevalonate (MVA) pathway when methanol or glucose was used as the carbon source. Our finding revealed that the sesquiterpene synthase module significantly increased the production when methanol was used. While the metabolic modules MK and PMK greatly improved carbon source utilization, cell growth, and titer when glucose was used. Additionally, we demonstrated the synthesis of β-farnesene from dual carbon source by replacing the α-bisabolene synthase with a β-farnesene synthase. This study establishes a platform strain that is capable to synthesize sesquiterpene from different carbon sources in P. pastoris. Moreover, it paves the way for the development of P. pastoris as a high-efficiency microbial cell factory for producing various chemicals, and lays foundation for large-scale synthesis of high value-added chemicals efficiently from methanol in P. pastoris.

Interlayer expansion and conductive networking of MoS2 nanoroses mediated by bio-derived carbon for enhanced potassium-ion storage

Potassium-ion batteries (PIBs) represent a promising battery technology for energy storage applications. Nevertheless, the progress of PIBs is still hindered by the lack of electrode materials that allow rapid and repeatable accommodation of the large K+ ions. Herein, a composite anode material containing interlayered-expanded MoS2 (55.6% larger) nanoroses in carbon nanonets (MoS2/C@CNs) is designed with the assistance of biomass bagasse, of which the dual carbon sources convert into interlayer and skeleton carbon, respectively. The unique structure facilitates electron/ion transport in the entire electrode and offers excellent structural stability, leading to much improved electrochemical performance compared to simple MoS2/C composite and pure MoS2. Furthermore, the role of electrolyte salts (potassium hexafluorophosphate and potassium bis(fluorosulfonyl)imide) and the electrolyte concentration on the interfacial properties in PIBs have been explored. The results indicate that the low-concentration potassium bis(fluorosulfonyl)imide electrolyte helps to produce optimized organic-inorganic solid electrolyte interface films, contributing to a capacity retention of 90% after 1,000 cycles at 2 A g-1.

Kinetic studies and dynamic modeling of sophorolipids production by Candida catenulata using different carbon sources

Abstract The kinetic study on sophorolipids (SLs) production by Candida catenulata from glucose, raw sunflower soapstock was investigated at different initial concentrations ranging from 0 to 100 g L−1. The Monod model with a maximum specific growth rate (μ max) of 0.0167 h−1 and half-saturation coefficient (K S ) of 6.91 g L−1 best described the cell growth kinetics of C. catenulata on glucose. The best-fitted constants of the Monod model for raw sunflower soapstock were μ max = 0.0157 h−1 and K S = 16.01 g L−1. Determination of Luedeking-Piret constants indicated SLs mainly produced as an associated growth product in the systems. Dynamic features of the fermentation were modeled using the obtained constants and results showed the prediction power of the developed model in describing the behavior of the process. Also, a modified kinetic model was developed for the dynamic modeling of the dual carbon sources system.

Synergistic Modification of Dandelion-Shaped Na3V2(PO4)3 with Triple Superimposed Conductive Networks by Dual-Carbon Sources for High Performance Sodium-Ion Batteries

Synergistic Modification of Dandelion-Shaped Na₃V₂(PO₄)₃ with Triple Superimposed Conductive Networks by Dual-Carbon Sources for High Performance Sodium-Ion Batteries

Preparation of LiFePO4 composite based on dual carbon sources of phytic acid and glucose and its performance for lithium extraction from salt lake

In this study, biomass phytic acid (PhyA) was used as phosphorus source and internal carbon source, and glucose (GC) was used as external carbon source to prepare dual carbon source LiFePO4 (GC/IC/LFP) electrode material containing intercalated carbon (IC) and coated carbon (GC). Based on the working principle of rocking chair lithium ion battery, a new electrochemical system was constructed to efficiently extract Li+ from salt lake brine with high Mg/Li ratio (53) and Na/Li ratio (416). The effects of electrolytic voltage and coexisting ions on the capacity of lithium extraction/insertion at room temperature were investigated. It was found that when the electrolytic voltage was 1.0 V, the insertion capacity of lithium in pure lithium solution could reach 43.67 mg·LiFePO4 (1 g)−1, which was 99.25 % of the theoretical capacity (44 mg). The lithium extraction capacity can reach 43.20 mg·LiFePO4 (1 g)−1, which is 98.92 % of the insertion capacity. In the simulated salt lake brine with a large number of coexisting ions, when the electrolytic voltage is 0.8 V, the lithium insertion capacity can reach 38.09 mg·LiFePO4 (1 g)−1, which is 86.57 % of the theoretical capacity, and the lithium extraction capacity can reach 35.00 mg·LiFePO4 (1 g)−1, which is 91.89 % of the insertion capacity. The system maintains high selectivity for Li+ extraction. The concentration of coexisting ions of K+, Mg2+, Na+ and Ca2+ decreased by more than 8800, 4500, 25,000 and 1200 times, respectively. The Mg/Li ratio decreased from 53 to 0.09, and the Na/Li ratio decreased from 416 to 0.10. After ten times of extraction, the electrode still has high coexisting Men+/Li+ separation performance, although the extraction performance is decreased to a certain extent.

Enhancing the high-rate performance of Li3V2(PO4)3/C for Li-ion batteries via a synergistic effect of dual carbon sources

Enhancing the high-rate performance of Li3V2(PO4)3/C for Li-ion batteries via a synergistic effect of dual carbon sources

Hybrid fed‐batch bioreactor operation design: control of substrate uptake enhances recombinant protein production in high‐cell‐density fermentations

AbstractBACKGROUNDThe hybrid fed‐batch bioreactor (HFBB) operation is a novel design method for high‐cell‐density fermentations. It employs fed‐batch and batch operations, starting with fed‐batch that in turn shifts to the next, and proceeds in successive cycles to enhance production and productivity by controlling the substrate uptake rate.RESULTSThe method was tested for the production of recombinant human growth hormone (rhGH) in Pichia pastoris under GAP promoter with carbon sources of (i) glucose and (ii) pre‐treated hydrolyzed sugar‐beet molasses containing equimolar glucose and fructose. The superior strategies were: (i) GH2, a HFBB with glucose feeding composed of ΔtFB = 1.5 h fed‐batch periods with continuous‐feed stream designed with the pre‐determined growth rate µ = 0.10 h−1, which shift in turn to ΔtB = 0.5 h batch periods; and (ii) MH2, a HFBB with molasses feeding designed in a similar way to GH2. The highest rhGH production attained in GH2 was 611 mg dm−3 at 8 h, whereas it was 625 mg dm−3 at 13.5 h in MH2. In GH2, rhGH production increased 1.37‐fold in half the cultivation time of GH2. However, in MH2 with dual carbon sources enriched with other substrates, higher rhGH production was obtained at the cost of lower productivity.CONCLUSIONThe HFBB is a powerful design method with a single carbon source which improves the productivity of high‐cell‐density fermentations. However, with molasses upon shifting to batch operations, the uptake of accumulated fructose is continued. Thus, the glamour of the HFBB is hindered for complex media fermentations to an extent, because multi‐carbon sources contribute to the growth during the batch periods by lengthening the cultivation time. © 2018 Society of Chemical Industry

Cellulose‐Templated, Dual‐Carbonized Na3V2(PO4)3 for Energy Storage with High Rate Capability

AbstractSodium‐ion rechargeable batteries are a promising candidate for large‐scale electrical energy storage systems, owing to the abundance of sodium resources. Herein, we report the development of carbon‐incorporated NASICON‐Na3V2(PO4)3 (NVP) as an active cathode material for Na‐ion batteries, using carboxymethyl cellulose (CMC) and sucrose as dual carbon sources. The interaction between CMC and sucrose resulted in the formation of a highly porous structure (surface area: 58.998 m2 g−1) with increased sp2 carbon species, facilitating mass and charge transportation. The specific capacity (104.99 mAh g−1) of dual‐carbonized CMC/sucrose‐NVP (CS‐NVP) was close to the theoretical capacity (117.6 mAh g−1). Furthermore, dual‐carbonized NVP exhibited stable cyclability, showing a specific capacity of 75.04 mA g−1 even at a high rate of 20 C.

N-Hexadecane and pyrene biodegradation and metabolization by Rhodococcus sp. T1 isolated from oil contaminated soil

Abstract The high-molecular weight polycyclic aromatic hydrocarbons (PAHs) pyrene and typical long chain alkane n -hexadecane are both difficult to degrade. In this study, n -hexadecane and pyrene degrading strain Rhodococcus sp. T1 was isolated from oil contaminated soil. Strain T1 could remove 90.81% n -hexadecane (2 vol%) and 42.79% pyrene (200 mg·L − 1 ) as a single carbon within 5 days, respectively. Comparatively, the degradation of pyrene increased to 60.63%, but the degradation of n -hexadecane decreased to 87.55% when these compounds were mixed. Additionally, identification and analysis of degradation metabolites of Rhodococcus sp. T1 in the above experiments showed that there were significant changes in alanine, methylamine, citric acid and heptadecanoic acid between sole and dual substrate degradation. The optimal conditions for degradation were then determined based on analysis of the pH, salinity, additional nutrient sources and liquid surface activity. Under the optimal conditions of pH 7.0, 35 °C, 0.5% NaCl, 5 mg·L − 1 of yeast extract and 90 mg·L − 1 of surfactant, the degradation increased in single or dual carbon sources. To our knowledge, this is the first study to discuss metabolite changes in Rhodococcus sp. T1 using sole substrate and dual substrate to enhance the long-chain alkanes and PAHs degradation potential.

Evaluation of date seed oil and date molasses as novel carbon sources for the production of poly(3Hydroxybutyrate-co-3Hydroxyhexanoate) by Cupriavidus necator H16 Re 2058/pCB113

Cupriavidus necator H16 Re2058/pCB113 could effectively utilize oil sources to synthesize P(3HB-co-3HHx). In this study, P(3HB-co-3HHx) biosynthesis procedure with optimally controlled (between 2–28) 3HHx mol% was established for C. necator H16 Re2058/pCB113 by regulating the amounts of dual carbon sources supplied; date molasses and date seed oil. Alone, date molasses supplied at 20 g/L total sugar equivalents to recombinant C. necator resulted in pure P(3HB) biosynthesis, with accumulation up to 28 wt% of cell dry weight (CDW), and effective total biomass of 4 g/L. Whereas, date seed oil supply alone or in combination with date molasses resulted in P(3HB-co-3HHx) biosynthesis. P(3HB-co-3HHx) with as high as 28 mol% 3HHx, up to 80 wt% of CDW and total biomass of 7.6 g/L were produced using 10 g/L date seed oil as the sole carbon source. The results of PHA production in the presence of date seed oil as a sole carbon source was obtained with a modest yield at a range of 0.38–0.62 g-PHA per g-date oil used. Gel permeation chromatography (GPC) analyses of these P(3HB-co-3HHx) copolymers exhibited weight average molecular weights (Mw) between 500 − 690 kDa. Differential scanning calorimetry (DSC) analyses showed Tm values of 157 °C and 85 °C for P(3HB) and P(3HB-co-28 mol% 3HHx), respectively. NMR analyses (1H and 13C) of P(3HB-co-3HHx) copolymers confirmed the incorporation of 3HHx monomers between 2–28 mol% depending on the supplied dual carbon source composition.

Formic acid as a secondary substrate for succinic acid production by metabolically engineered Mannheimia succiniciproducens.

There has been much effort exerted to reduce one carbon (C1) gas emission to address climate change. As one promising way to more conveniently utilize C1 gas, several technologies have been developed to convert C1 gas into useful chemicals such as formic acid (FA). In this study, systems metabolic engineering was utilized to engineer Mannheimia succiniciproducens to efficiently utilize FA. 13 C isotope analysis of M. succiniciproducens showed that FA could be utilized through formate dehydrogenase (FDH) reaction and/or the reverse reaction of pyruvate formate lyase (PFL). However, the naturally favored forward reaction of PFL was found to lower the SA yield from FA. In addition, FA assimilation via FDH was found to be more efficient than the reverse reaction of PFL. Thus, the M. succiniciproducens LPK7 strain, which lacks in pfl, ldh, pta, and ack genes, was selected as a base strain. In silico metabolic analysis confirmed that utilization of FA would be beneficial for the enhanced production of SA and suggested FDH as an amplification target. To find a suitable FDH, four different FDHs from M. succiniciproducens, Methylobacterium extorquens, and Candida boidinii were amplified in LPK7 strain to enhance FA assimilation. High-inoculum density cultivation using 13 C labeled sodium formate was performed to evaluate FA assimilation efficiency. Fed-batch fermentations of the LPK7 (pMS3-fdh2 meq) strain was carried out using glucose, sucrose, or glycerol as a primary carbon source and FA as a secondary carbon source. As a result, this strain produced 76.11 g/L SA with the yield and productivity of 1.28 mol/mol and 4.08 g/L/h, respectively, using sucrose and FA as dual carbon sources. The strategy employed here will be similarly applicable in developing microorganisms to utilize FA and to produce valuable chemicals and materials from FA.

Enhancing cell growth and lutein productivity of Desmodesmus sp. F51 by optimal utilization of inorganic carbon sources and ammonium salt

The type and concentration of inorganic carbon and nitrogen sources were manipulated to improve cell growth and lutein productivity of Desmodesmus sp. F51. Using nitrate as nitrogen source, the better cell growth and lutein accumulation were obtained under 2.5% CO2 supply when compared to the addition of NaHCO3 or Na2CO3. To solve the pH variation problem of ammonium consumption, the strategy of using dual carbon sources (NaHCO3 and CO2) was explored. A lower bicarbonate-C: ammonium-N ratio led to a lower culture pH as well as lower lutein productivity, but significantly enhanced the auto-flocculation efficiency of the microalgal cells. The highest biomass productivity (939mg/L/d) and lutein productivity (5.22mg/L/d) were obtained when the bicarbonate-C/ammonium-N ratio and ammonium-N concentration were 1:1 and 150mg/L, respectively. The lutein productivity of 5.22mg/L/d is the highest value ever reported in the literature using batch phototrophic cultivation.

Efficient anaerobic production of succinate from glycerol in engineered Escherichia coli by using dual carbon sources and limiting oxygen supply in preceding aerobic culture

Glycerol is an important resource for production of value-added bioproducts due to its large availability from the biodiesel industry as a by-product. In this study, two metabolic regulation strategies were applied in the aerobic stage of a two-stage fermentation to achieve high metabolic capacities of the pflB ldhA double mutant Escherichia coli strain overexpressing phosphoenolpyruvate carboxykinase (PCK) in the subsequent anaerobic stage: use of acetate as a co-carbon source of glycerol and restriction of oxygen supply in the PCK induction period. The succinate concentration achieved 926.7mM with a yield of 0.91mol/mol during the anaerobic stage of fermentation in a 1.5-L reactor. qRT-PCR indicated that the two strategies enhanced transcription of genes related with glycerol metabolism and succinate production. Our results showed this metabolically engineered E. coli strain has a great potential in producing succinate using glycerol as carbon source.

Homo-succinic acid production by metabolically engineered Mannheimia succiniciproducens

Succinic acid (SA) is a four carbon dicarboxylic acid of great industrial interest that can be produced by microbial fermentation. Here we report development of a high-yield homo-SA producing Mannheimia succiniciproducens strain by metabolic engineering. The PALFK strain (ldhA-, pta-, ackA-, fruA-) was developed based on optimization of carbon flux towards SA production while minimizing byproducts formation through the integrated application of in silico genome-scale metabolic flux analysis, omics analyses, and reconstruction of central carbon metabolism. Based on in silico simulation, utilization of sucrose would enhance the SA production and cell growth rates, while consumption of glycerol would reduce the byproduct formation rates. Thus, sucrose and glycerol were selected as dual carbon sources to improve the SA yield and productivity, while deregulation of catabolite-repression was also performed in engineered M. succiniciproducens. Fed-batch fermentations of PALFK with low- and medium-density (OD600 of 0.4 and 9.0, respectively) inocula produced 69.2 and 78.4g/L of homo-SA with yields of 1.56 and 1.64mol/mol glucose equivalent and overall volumetric SA productivities of 2.50 and 6.02g/L/h, respectively, using sucrose and glycerol as dual carbon sources. The SA productivity could be further increased to 38.6g/L/h by employing a membrane cell recycle bioreactor system. The systems metabolic engineering strategies employed here for achieving homo-SA production with the highest overall performance indices reported to date will be generally applicable for developing superior industrial microorganisms and competitive processes for the bio-based production of other chemicals as well.

Improving carbohydrate production of Chlorella sorokiniana NIES-2168 through semi-continuous process coupled with mixotrophic cultivation.

Biofuels from microalgae is now a hot issue of great potential. However, achieving high starch productivity with photoautotrophic microalgae is still challenging. A feasible approach to enhance the growth and target product of microalgae is to conduct mixotrophic cultivation. The appropriate acetate addition combined with CO2 supply as dual carbon sources (i.e., mixotrophic cultivation) could enhance the cell growth of some microalgae species, but the effect of acetate-mediated mixotrophic culture mode on carbohydrate accumulation in microalgae remains unclear. Moreover, there is still lack of the information concerning how to increase the productivity of carbohydrates from microalgae under acetate-amended mixotrophic cultivation and how to optimize the engineering strategies to achieve the goal. This study was undertaken to develop an optimal acetate-contained mixotrophic cultivation system coupled with effective operation strategies to markedly improve the carbohydrate productivity of Chlorella sorokiniana NIES-2168. The optimal carbohydrate productivity of 695 mg/L/d was obtained, which is the highest value ever reported. The monosaccharide in the accumulated carbohydrates is mainly glucose (i.e., 85-90%), which is very suitable for bio-alcohols fermentation. Hence, by applying the optimal process developed in this study, C. sorokiniana NIES-2168 has a high potential to serve as a feedstock for subsequent biofuels conversion.

Laccase Production by Trameteshirsuta, Characterization, and Its Capability of Decoloring Chlorophyll

The present study focused on laccase production, characterization, and its involvement in chlorophyll decolorization. Extracellular laccase, with the highest activity of 11 U/ml on day 8, was efficiently produced from Trametes hirsuta in 5 l bioreactor with optimized media comprising dual carbon sources, glucose and water hyacinth. A laccase was then purified from the supernatant to homogeneity with purification fold of 9.51 and recovery of 39.8% and an estimated molecular mass of 62 kDa by SDS-PAGE. The laccase showed activity at pH 2-6 and temperature 30-80°C and was relatively thermally stable at below 70°C and neutral pH. The laccase was applied to decolorize chlorophyll under different factors: temperature, pH, mediator, metal ions, and enzyme dosage. Other fungal laccases were also found to be able to degrade chlorophyll with rating from 52% to 88% following 1 h treatment with two laccase dosages (5 or 10 U/ml) in the absence of any other mediators at room temperature. These findings may be an important step in developing new, important, and commercially viable industrial applications for laccase enzymes.

Dual Carbon Coating Used in the Preparation of LiFePO<sub>4</sub>/C Cathode Material

The LiFePO4/C cathode material was synthesized by two–step addition of dual carbon sources method based on the in situ polymerization method combining with two–step sintering process. In this study, the structure and morphology have been studied systematically by X–ray diffraction (XRD) and scanning electron microscope (SEM).The electrochemical performances have been shown by the charge/discharge capacity, rate property, cycle performance. It was evidenced that the two–step addition of dual carbon sources had remarkable advantages, including the more complete coating carbon, and the improvement in the electrochemical performance of LiFePO4/C.

Production of Bacterial Cellulose from Gluconacetobacter persimmonis GH-2 using Dual and Cheaper Carbon Sources

Bacterial cellulose is an exopolysaccharide produced by various species of bacteria such as in the genera Gluconacetobacter, Agrobacterium, Achromobacter, Azotobacter, Rhizobium, Sarcina, Salmonella, Enterobacter, etc. In recent years, bacterial cellulose has been focused for the development of acoustic diaphragms, specialty membranes, biomedical wound care products, scaffold for tissue engineering, etc. In this study, effective culture method to produce bacterial cellulose from cheaper and dual carbon sources by Gluconacetobacter persimmonis was examined. Various fruit juices including pineapple, pomegranate, muskmelon, water melon, tomato, orange, and also molasses, starch hydrolyzate, sugarcane juice, coconut water, coconut milk were used as alternative carbon sources for bacterial cellulose production. Out of which muskmelon gave a highest cellulose yield of 8.08 g/L. Also glucose, fructose, sucrose, maltose, lactose, mannitol, inositol and glycerol were used in combination of two (1:1) as dual carbon sources. Out of these dual carbon sources, the combination of fructose and sucrose (1:1) gave the highest cellulose yield of 8.79 g/L. In this study, an attempt was made to reduce the cost of production medium for cellulose by using natural cheaper carbon sources.