Effect Of Different Carbon Sources Research Articles

Numerical Simulation of Ethanol Production for Different Carbon Sources Using Thermotolerant Kluyveromyces Marxianus

During process of fermentation a variety of parameters effect on ethanol production, current work focusses to investigate the effect of different carbon sources on ethanol production using numerical simulation. The fermentation process was carried out using microprocessor-controlled fermenter in which different types of carbon sources were studied like glucose, sucrose and molasses from 10 % to 15% of range. The model proposed by Monod was found to be more appropriate for describing the batch growth and ethanol production using kluyveromyces marxianus. The maximum yield of ethanol production took place using 15 % molasses as carbon source. The maximum ethanol production (76 g/l) was observed at 15% molasses, as for sucrose and glucose are concerned it gives lower value of ethanol production up to 73g/l by keeping other operational parameter under optimized condition such are 35oC, 300rpm, 0.2vvm/l and pH5.5. Approximately same results were achieved by using experimental data and model execution.

Glycerol inhibition of melanin biosynthesis in the environmental Aeromonas salmonicida 34melT.

The environmental strain Aeromonas salmonicida subsp. pectinolytica 34melT produces abundant melanin through the homogentisate pathway in several culture media, but unexpectedly not when grown in a medium containing glycerol. Using this observation as a starting point, this study investigated the underlying causes of the inhibition of melanin synthesis by glycerol, to shed light on factors that affect melanin production in this microorganism. The effect of different carbon sources on melanin formation was related to the degree of oxidation of their C atoms, as the more reduced substrates delayed melanization more than the more oxidized ones, although only glycerol completely abolished melanin production. Glyphosate, an inhibitor of aromatic amino acid synthesis, did not affect melanization, while bicyclopyrone, an inhibitor of 4-hydroxyphenylpyruvate dioxygenase (Hpd), the enzyme responsible for the synthesis of homogentisate, prevented melanin synthesis. These results showed that melanin production in 34melT depends on the degradation of aromatic amino acids from the growth medium and not on de novo aromatic amino acid synthesis. The presence of glycerol changed the secreted protein profile, but none of the proteins affected could be directly connected with melanin synthesis or transport. Transcription analysis of hpd, encoding the key enzyme for melanin synthesis, showed a clear inhibition caused by glycerol. The results obtained in this work indicate that a significant decrease in the transcription of hpd, together with a more reduced intracellular state, would lead to the abolishment of melanin synthesis observed. The effect of glycerol on melanization can thus be attributed to a combination of metabolic and regulatory effects.

An efficient constitutive expression system for Anti-CEACAM5 nanobody production in the yeast Pichia pastoris

Nanobodies offer multiple advantages over conventional antibodies in terms of size, stability, solubility, immunogenicity, and production costs, with improved tumor uptake and blood clearance. Additionally, the recombinant expression of nanobodies is robust in various expression systems, such as Escherichia coli, Saccharomyces cerevisiae and Pichia pastoris. P. pastoris is the most widely used microorganism for nanobody production, but all or almost all expression vectors developed for this system are based on the regulated promoter of the alcohol oxidase 1 gene (AOX1) that requires methanol for full induction. In this study, a constitutive anti-CEACAM5 nanobody expression system was constructed under the control of a glyceraldehyde-3-phosphate dehydrogenase promoter (GAP) promoter. The effects of different carbon sources and pH on nanobody expression were evaluated in shaking flask cultures. After 96 h of constitutive expression in shaking flask, a yield of 51.71 mg/L was obtained. In addition, this constitutive expression system produced nanobodies at equivalent yield and affinity to that produced by methanol-induced expression. The results of this study indicated that the use of a constitutive expression system is a promising alternative for the production of nanobodies applied for cancer diagnosis and therapy.

Effect of Different Carbon Sources on in Vitro Shoot Regeneration of Petunia Hybrid Hort. Vilm

Effect of Different Carbon Sources on in Vitro Shoot Regeneration of Petunia Hybrid Hort. Vilm

The effect of different carbon sources on LiFePO4 for electrochemical performance

ABSTRACTThe LiFePO4 material was successfully prepared by an effective and controllable hydrothermal method with the assistance of ethylene glycol (EG). Then, different carbon sources (glucose and carbon nanotubes (CNTs)) were used to synthesize LiFePO4/C and LiFePO4/CNTs composites and roundly investigated the performance of composites. The X-ray diffraction (XRD) showed that the composites had excellent crystallinity. Electrochemical performance tests demonstrated that the LiFePO4/CNTs composite exhibited the best discharge specific capacity. The special capacity was 154.6 mAh/g at 0.1C, which was higher than LiFePO4/C composite (144.8 mAh/g at 0.1C). The cycling performances of LiFePO4/CNTs composite showed better performances than LiFePO4/C composite at 1C and 10C. It can be attributed to a three-dimensional network structure of LiFePO4/CNTs that enhanced the electrochemical performance.

Transcriptome remodeling of Pseudomonas putida KT2440 during mcl-PHAs synthesis: effect of different carbon sources and response to nitrogen stress

Bacterial response to environmental stimuli is essential for survival. In response to fluctuating environmental conditions, the physiological status of bacteria can change due to the actions of transcriptional regulatory machinery. The synthesis and accumulation of polyhydroxyalkanoates (PHAs) are one of the survival strategies in harsh environments. In this study, we used transcriptome analysis of Pseudomonas putida KT2440 to gain a genome-wide view of the mechanisms of environmental-friendly biopolymers accumulation under nitrogen-limiting conditions during conversion of metabolically different carbon sources (sodium gluconate and oleic acid). Transcriptomic data revealed that phaG expression is associated with medium-chain-length-PHAs’ synthesis not only on sodium gluconate but also on oleic acid, suggesting that PhaG may play a role in this process, as well. Moreover, genes involved in the β-oxidation pathway were induced in the PHAs production phase when sodium gluconate was supplied as the only carbon and energy source. The transition from exponential growth to stationary phase caused a significant expression of genes involved in nitrogen metabolism, energy supply, and transport system. In this study, several molecular mechanisms, which drive mcl-PHAs synthesis, have been investigated. The identified genes may provide valuable information to improve the efficiency of this bioprocess and make it more economically feasible.

Feasible microbial accumulation of triacylglycerides from crude glycerol

AbstractBACKGROUNDCrude glycerol, a by‐product of the biodiesel production industry, was used to produce intracellular storage polymers for waste valorization. The enrichment of a mixed microbial culture (MMC) in microorganisms with the ability to accumulate intracellular polymers was performed in a sequencing batch reactor (SBR) submitted to feast–famine conditions. The effect of different carbon sources in the accumulation of biopolymers was investigated.RESULTSA MMC enriched in yeast and bacteria was obtained using crude glycerol as feedstock. Accumulation experiments performed with crude glycerol, synthetic glycerol and synthetic methanol showed the feasibility of the MMC to produce different biopolymers. Triacylglyceride (TAG) accumulation up to 46 wt% in yeast cells was promoted by the presence of residual lipids in crude glycerol. However, bacteria from class Betaproteobacteria used glycerol mainly to accumulate 28 wt% of polyglucose (PG) and methanol as carbon source for cell growth.CONCLUSIONSAs waste valorization, a possible advantage which comes out of the present study is the use of open, non‐sterile and non‐defined systems to produce TAGs. These TAGs can potentially re‐enter the biodiesel production process helping on the maximisation of the feedstock used in this process. © 2018 Society of Chemical Industry

Effect of different carbon sources on denitrification performance, microbial community structure and denitrification genes

Solid and liquid organic substances as carbon sources for denitrification process were deeply explored. In this study, the effect of three carbon sources, referred to as poly (3-hydroxybutyrate-co-3-hydroxyvalerate)/poly (lactic acid) (PHBV/PLA) polymer, glucose and CH3COONa, on denitrification performance, microbial community and functional genes were investigated. It was found that maximum denitrification rates of 0.37, 0.46 and 0.39gN/(L·d) were achieved in PHBV/PLA, glucose and CH3COONa supported denitrification systems, respectively. Meanwhile, Illumina MiSeq sequencing revealed that three carbon sources led to different microbial community structures. It can be seen that Brevinema/Thauera/Dechloromonas, Tolumonas/Thauera/Dechloromonas, Thauera dominated in the PHBV/PLA, glucose and CH3COONa supported denitrification systems, respectively. Transcriptome-based analysis further indicated that the glucose supported denitrification system showed the highest FPKM values (the fragments per kilobase per million mapped reads) of the genes participating in the dissimilatory nitrate reduction process, corresponding to the greatest effluent NH4+-N concentration. A better knowledge of effect of different carbon sources on denitrification process will be significant for nitrate removal in practice.

<b>Effects of glutathione supplementation and carbon source during somatic embryogenesis of <i>Acca sellowiana</i> (O.Berg) Burret (Myrtaceae)

The present study intended to investigate the effects of different glutathione (GSH) levels (0, 0.1, 0.5 and 1 mM) on the somatic embryogenesis (SE) induction of Acca sellowiana . Besides, we evaluated the effect of different carbon sources (sucrose and maltose) on the somatic embryos conversion. GSH-supplemented treatments resulted in improved SE induction rates (~70%) as compared to the control GSH-free (~35%) after 50 days of culture. The total number of somatic embryos obtained did not differ between treatments, but significant differences were observed for the embryonic stages after 80 days of culture. After 80 days of culture, 0.5 and 1 mM GSH-supplemented treatments showed the largest amount of torpedo-staged somatic embryos. In contrast, treatments supplemented with 0 and 0.1 mM GSH showed equal amounts of somatic embryos at all embryonic stages. These results indicate that GSH accelerates the SE induction process and increases the synchrony of the somatic embryo formation of A. sellowiana . The use of maltose for the somatic embryos conversion, as compared to sucrose, did not influence the conversion rate of normal chlorophyllous somatic embryos, but increased the formation of normal achlorophyllous somatic plantlets. This finding can be attributed to the rapid hydrolysis of sucrose, contributing to an enhanced chlorophyll synthesis.

Study on Betalains in Celosia cristata Linn. Callus Culture and Identification of New Malonylated Amaranthins.

Betacyanins and betaxanthins were characterized and determined in an intensely pigmented red-colored callus culture of Celosia cristata L. (Amaranthaceae). A new malonyl derivative, 6'- O-malonyl-amaranthin (celoscristatin) was isolated and identified by spectroscopic and mass spectrometric techniques. Its stereoisomer, 4'- O-malonyl-amaranthin (celoscristatin acyl-migrated), as well as its 15 R diastereomer were also detected in the callus as a result of the malonyl group migration in celoscristatin/isoceloscristatin, respectively. Amaranthin occurs in the callus as the major betacyanin, followed by celoscristatin, betanin, phyllocactin, and other minor betacyanins. The effect of different carbon sources on the growth rates of the Celosia callus as well as on betalains profiles in the callus cultures was studied. High dopamine content in the callus culture was determined and compared with the content in C. cristata inflorescences. The dopamine-based betalain (miraxanthin V) was detected as the main betaxanthin in the callus, however, at a concentration level much lower than that of the identified betacyanins. The studied callus culture of C. cristata can accumulate betalains in amounts which approach the quantities produced by most known high-yielding plant species.

Effects of different carbon sources and C/N ratios on the simultaneous anammox and denitrification process

The simultaneous anammox and denitrification (SAD) process is an emerging treatment for wastewaters containing nitrogen pollution and organics. However, there is little research on the effect of organic matter types on the SAD process. In this study, two reactors, one with glucose (R1) and the other with acetate (R2), were used to investigate the effects of different carbon sources and C/N ratios on the SAD process. The nitrogen removal performance, functional gene abundance, biomass activity and microbial community structures of the two reactors were analyzed and compared. Results showed that a desirable nitrogen removal efficiency (NRE) was obtained at the C/N ratio of 1.2 in R1, whereas a similar NRE could be achieved at a C/N ratio of 0.8 in R2, which was more susceptible to a high C/N ratio. Moreover, at high C/N ratios, the microbial species diversity of R1 was higher than that of R2. High-throughput sequencing analysis revealed that anammox bacteria predominated at low COD, but denitrifying bacteria grew rapidly at high C/N ratio. Removal of NO3−-N in the glucose-driven reactor appeared to be more depended on other heterotrophic bacteria other than denitrification bacteria. In general, the glucose-driven reactor was more stable and resistant to high C/N ratios during the SAD process than the acetate-driven one. Results of this study provide information for practical treatment of wastewater with high nitrogen contents.

Use of different carbon sources for the biofloc system during the grow-out culture of common carp (Cyprinus carpio L.) fingerlings

A 10weeks feeding trial was carried out to evaluate the effects of different carbon sources (sugar beet molasses: SBM+BFT, sugar: S+BFT, corn starch: CS+BFT) on water quality, growth performance, digestive enzymes activity, biofloc and fish microbial community and composition in biofloc based system for common carp fingerlings. Three hundred healthy fingerlings (22.5±0.2g) were randomly assigned to 12 rectangle tanks (70L) at a density of 8.02kgm−3. Fish in BFT treatments were fed at 75% of the daily feeding rate (DFI) of control. Results showed a significant difference in water quality parameters among different culture systems; CS+BFT had the lowest amount of total ammonia nitrogen (TAN) at the end of culture period. No difference was observed between the BFT treatments in case of nitrite-N and nitrate N after 10weeks and total suspended solids (TSS) also experienced a decline during the experiment. The fish yield was the highest in CS+BFT, which also had the lowest significant feed conversion ratio (P<0.05). This was coincidental with the highest activity for total protease, lipase and amylase in BFT treatments when compared with the control (P<0.05). A significantly higher body protein and lipid content and lower carbohydrate was seen in CS+BFT treatment (P<0.05). Different carbon sources did not affect on protein and carbohydrate content of flocs but CS+BFT significantly caused an increase in lipid and ash content in microbial flocs (P<0.05).The fingerlings essential fatty acids affected by different carbon sources and the lowest values were found in BFT treatments which differed significantly with control (P<0.05). Microbial community was analyzed by PCR-DGGE as well as conventional method and results indicated the changes in both bacterial intensity and diversity among the different culture systems. Among the different carbon sources used, corn starch has increased the content of total culturable bacteria and lactobacillus spp. in tanks and fish hindgut. Overall, this study suggests that microbial flocs formed in corn starch based biofloc can improve common carp growth performance and tanks water quality under zero water exchange and hence ensures sustainability.

Effects of different carbon sources on enhanced biological phosphorus removal and "Candidatus Accumulibacter" community composition under continuous aerobic condition.

Previous studies have shown that enhanced biological phosphorus removal (EBPR) performance under continuous aerobic conditions always eventually deteriorates; however, the speed at which this happens depends on the carbon source supplied. The published data suggest that propionate is a better carbon source than acetate is for maintaining operational stability, although it is not clear why. A lab-scale sequencing batch reactor was run initially under conventional anaerobic/aerobic conditions with either acetate or propionate as the carbon source. Chemical and microbiological analyses revealed that both sources performed as expected for such systems. When continuous aerobic conditions were imposed on both these established communities, marked shifts of the "Candidatus Accumulibacter" clades were recorded for both carbon sources. Here, we discuss whether this shift could explain the prolonged EBPR stability observed with propionate.

Effect of synthetic and natural media on lipid production from Fusarium oxysporum

Abstract Background Dependence on fossil resources, for the production of fuels and energy, has resulted in environmental and financial problems, which require our immediate action in order to reverse the situation. Use of renewable sources for the production of fuels and energy is an important alternative with biodiesel remains as one of the promising options. Aim of this work is to evaluate the fungus Fusarium oxysporum for its potentials to accumulate microbial lipids when grown on synthetic media and saccharified sweet sorghum stalks. Results The effect of different carbon sources, nitrogen sources and C/N ratio on the lipid production was initially examined, which resulted in a lipid concentration of 4.4 g/L, with lipid content of 42.6% w/w. Sweet sorghum stalks were able to support growth and lipid production of the fungus, both as carbon source and as nitrogen source. It was also shown that saccharification of the dried stalks is an important step to increase lipid production. Removal of the remaining stalk solids enabled the lipid production during cultivation in increased initial solids of up to 16 w/w. This resulted in a lipid production of 3.81 g/L. Conclusions It was demonstrated that F. oxysporum can be used as an efficient oleaginous microorganism, with sweet sorghum serving as an excellent raw material for the cultivation of the fungus. The lipids obtained during this work were also found to have a fatty acid profile with good potentials to be used for biodiesel production.

The effect of different carbon sources on water quality, microbial community and structure of biofloc systems

The main objective of this work was to investigate how different carbon sources affect microbial diversity of biofloc. The experiment consisted of the control and three types of biofloc systems using different carbon sources, tapioca starch (TS), plant cellulose (PC) and the combination of tapioca starch and plant cellulose (TS+PC), and conducted for 42days in twelve 300L Fiber Reinforce Plastic (FRP) circular tanks. Pelteobagrus vachelli (n=72) of mean weight (38.1±5.9g) were randomly distributed into twelve tanks. Community characterization of total bacteria and ammonia-oxidizing bacteria in all treatments were respectively investigated by Illumina MiSeq analysis using PCR-amplified 16S rRNA gene fragments (primer 27F-338R for total bacteria and primer CTO189F-CTO654R for ammonia-oxidizing bacteria). The ammonia-nitrogen concentration in control (3.6±4.6mgL−1) was significantly higher than that in all biofloc systems (2.4±2.9mgL−1, 1.8±2.4mgL−1 and 2.2±2.5mgL−1 for TS, PC and TS+PC, respectively) (P<0.05). Weight gain ratio in TS was significantly higher than the control (P<0.05), while there is no significant difference between the control and treatment groups added plant cellulose (PC and TS+PC) (P>0.05). The Illumina MiSeq sequencing results showed that biofloc systems incorporating plant cellulose treatment groups had a higher total bacterial diversity and greater microbial richness than those with no plant cellulose treatment groups (Control and TS) (P<0.05). There was significant increase of Betaproteobacteria in the control and TS treatments, whereas Alphaproteobacteria was higher in treatment groups added plant cellulose (P<0.05). Illumina sequencing analysis of ammonia-oxidizing bacteria V3 region also detected a higher community diversity in biofloc systems (Shannon index, >1.21; Simpson index, <0.3949) compared to control (Shannon index, 0.84; Simpson index, 0.6149). We conclude that organic carbon sources in biofloc system can decrease ammonia‑nitrogen concentration and improve the community diversities of overall and ammonia-oxidizing bacteria.

Effect of different carbon sources on performance of an A2N-MBR process and its microbial community structure

Effect of different carbon sources on purification performance and change of microbial community structure in a novel A2N-MBR process were investigated. The results showed that when fed with acetate, propionate or acetate and propionate mixed (1:1) as carbon sources, the effluent COD, NH4 +-N, TN and TP were lower than 30, 5, 15 and 0.5 mg∙L–1, respectively. However, taken glucose as carbon source, the TP concentration of effluent reached 2.6 mg∙L–1. Process analysis found that the amount of anaerobic phosphorus release would be the key factor to determine the above effectiveness. The acetate was beneficial to the growth of Candidatus Accumulibacter associated with biological phosphorus removal, which was the main cause of high efficiency phosphorus removal in this system. In addition, it could eliminate the Candidatus Competibacter associated with glycogen-accumulating organisms and guarantee high efficiency phosphorus uptake of phosphorus accumulating organisms in the system with acetate as carbon source.

Process engineering of cellulosic n-butanol production from corn-based biomass using Clostridium cellulovorans

The cellulolytic Clostridium cellulovorans has been engineered to produce n-butanol from low-value lignocellulosic biomass by consolidated bioprocessing (CBP). The objective of this study was to establish a robust cellulosic biobutanol production process using a metabolically engineered C. cellulovorans. First, various methods for the pretreatment of four different corn-based residues, including corn cob, corn husk, corn fiber, and corn bran, were investigated. The results showed that better cell growth and a higher concentration of n-butanol were produced from corn cob that was pretreated with sodium hydroxide. Second, the effects of different carbon sources (glucose, cellulose and corn cob), basal media and culture pH values on butanol production were evaluated in the fermentations performed in 2-L bioreactors to identify the optimal CBP conditions. Finally, the engineered C. cellulovorans produced butanol with final concentration >3 g/L, yield >0.14 g/g, and selectivity >3 g/g from pretreated corn cob at pH 6.5 in CBP. This study showed that the fermentation process engineering of C. cellulovorans enabled a high butanol production directly from agricultural residues.

Glucose triggers the cytotoxicity of Citrobacter sp. R1 against Microcystis aeruginosa

Algicidal bacteria offer a promising option for killing Microcystis aeruginosa, one notorious cyanobacteria causing harmful algal blooms. In this study, Citrobacter sp. R1 presented high algicidal activity (81.6±2.2%, 72h) against M. aeruginosa when cultured using glucose, while it showed no algicidal activity (0±3.4%) when cultured using wheat bran, suggesting that appropriate carbon source is crucial for algicidal bacteria in killing M. aeruginosa. The underlying algicidal mechanism of strain R1 was explored by studying the effect of different carbon sources (glucose and wheat bran) on its key algicidal gene expression and total protein translation. While the glycogen synthase gene (glgA), cloned from strain R1 via transposon mutagenesis, was for the first time related to algicidal activity, its transcriptional level was not positively correlated with the algicidal activity of strain R1. We found that, the translation of total protein of strain R1 was relatively less when cultured with glucose, compared to growth with wheat bran. This indicated that the functional algicidal gene of strain R1 exerts its algicidal activity at protein translational level. These findings not only reveal the importance of appropriate carbon source for strain R1 for controlling M. aeruginosa, but also bring insights into its underlying algicidal mechanism.

Effect of carbon sources on the growth and ethanol production of native yeast Pichia kudriavzevii ITV-S42 isolated from sweet sorghum juice.

The importance of non-Saccharomyces yeast species in fermentation processes is widely acknowledged. Within this group, Pichia kudriavzevii ITV-S42 yeast strain shows particularly desirable characteristics for ethanol production. Despite this fact, a thorough study of the metabolic and kinetic characteristics of this strain is currently unavailable. The aim of this work is to study the nutritional requirements of Pichia kudriavzevii ITV-S42 strain and the effect of different carbon sources on the growth and ethanol production. Results showed that glucose and fructose were both assimilated and fermented, achieving biomass and ethanol yields of 0.37 and 0.32gg-1, respectively. Glycerol was assimilated but not fermented; achieving a biomass yield of 0.88gg-1. Xylose and sucrose were not metabolized by the yeast strain. Finally, the use of a culture medium enriched with salts and yeast extract favored glucose consumption both for growth and ethanol production, improving ethanol tolerance reported for this genre (35gL-1) to 90 gL-1 maximum ethanol concentration (over 100%). Furthermore Pichia kudriavzevii ITV-S42 maintained its fermentative capacity up to 200gL-1 initial glucose, demonstrating that this yeast is osmotolerant.

Brevibacillus Thermoruber 9X-GLC, Bacteria Isolated from Hot Compost, Producer of a Beta-Glucosidase Resistant to Glucose Inhibition

The thermotolerant strain Brevibacillus thermoruber 9X-GLC produces large amounts of β-D-glucosidase and cellobiohydrolase when grown on cellobiose and avicel. 9X-GLC was isolated from hot compost of sugarcane bagasse and filter mud and selected for its high enzymatic activity from a Bacilli collection of 77 isolates from soils and compost. Culture supernatants and ultrafiltered concentrates from shaken flask cultures of 9X-GLC were tested for their β-D-glucosidase activity and stability under different conditions of temperature, pH and glucose concentration. The concentrated supernatant from 9X-GLC cultures on cellobiose as sole carbon source had its highest β-D-glucosidase activity at 55°C; pH= 6.0 and retained 60% of its activity at a glucose concentration of up to 200 mM. The effect of different carbon sources on growth and β-D-glucosidase activity of concentrated supernatants was tested in 48 h shaken flask cultures of 9X-GLC. Glucose, cellodextrin and cellobiose supported high cell densities (>2×108 CFU/ml), whereas cellobiose and cellodextrin provided the best substrates for β-D-glucosidase production. The putative gene encoding β-D-glucosidase from 9X-GLC was obtained from PCR amplification and sequenced. The sequence of the putative structural gene of 2085 bp reveals 6 catalytic domains with high (>90%) homology to bacterialglycosidases.