Acid Fermentation Broth Research Articles

Modulation effect of sulfated polysaccharide from Sargassum fusiforme on gut microbiota and their metabolites in vitro fermentation.

The present study demonstrated the digestion behavior and fermentation characteristics of a sulfated polysaccharide from Sargassum fusiforme (SFSP) in the simulated digestion tract environment. The results showed that the molecular weight of two components in SFSP could not be changed by simulated digestion, and no free monosaccharide was produced. This indicates that most of SFSP can reach the colon as prototypes. During the fermentation with human intestinal flora in vitro, the higher-molecular-weight component of SFSP was utilized, the total sugar content decreased by 16%, the reducing sugar content increased, and the galactose content in monosaccharide composition decreased relatively. This indicates that SFSP can be selectively utilized by human intestinal flora. At the same time, SFSP also changed the structure of intestinal flora. Compared with the blank group, SFSP significantly increased the abundance of Bacteroidetes and decreased the abundance of Firmicutes. At the genus level, the abundances of Bacteroides and Megamonas increased, while the abundances of Shigella, Klebsiella, and Collinsella decreased. Moreover, the concentrations of total short-chain fatty acids (SCFAs), acetic, propionic and n-butyric acids significantly increased compared to the blank group. SFSP could down-regulate the contents of trimethylamine, piperidone and secondary bile acid in fermentation broth. The contents of nicotinic acid, pantothenic acid and other organic acids were increased. Therefore, SFSP shows significant potential to regulate gut microbiota and promote human health.

A Novel Bio-Purification Process Employing an Engineered E. coli Strain for Downstream Processing of Lactic Acid Solutions from the Fermentation of Agro-Industrial by-Products.

This study aims to integrate a novel bio-purification process employing an engineered E. coli strain in the downstream processing of lactic acid (LA) fermentation broths from low-cost renewable biological feedstocks. Fermentation broth of candy waste and digestate mixture was used as a real biological feedstock. An engineered E. coli strain that selectively catabolize impurities without catabolizing LA was initially adapted on the biological feedstock, followed by shake flask experiments to prove the bio-purification concept. Scale-up and validation in a bench-scale bioreactor followed, before developing a semi-continuous membrane bioreactor (MBR) bio-purification process. The MBR bio-purification was assessed with biological feedstocks which simulated ultrafiltration or nanofiltration permeates. Incomplete removal of impurities and increased fouling was observed in the case of the ultrafiltration permeate. Contrarily, the nanofiltration permeate was successfully treated with MBR bio-purification, since low membrane fouling, 100% maltose and acetic acid removal, and no LA catabolism was achieved. MBR bio-purification as a post-treatment step in the downstream processing of LA was demonstrated as a promising technology for increasing the purity of LA solutions.

Comparison of different aerobic sludge on enriching polyhydroxyalkanoate mixed microbial culture using lactic acid fermentation broth of agricultural wastes

Lactic acid fermentation broth derived from pig manure and apple waste is a potential high-quality feedstock for production of the biodegradable plastic polyhydroxyalkanoate (PHA). Enrichment of active PHA-synthesizing bacterial consortia, namely mixed microbial culture (MMC), is an important factor in high-efficiency synthesis of PHA. In this study, two types of aerobic sludge (pig farm sludge and municipal sludge) were selected to acquire active MMCs in the enrichment process with sludge retention times of 2 and 8 days using the lactic acid fermentation broth. Batch reactors and PHA accumulation reactors were used to evaluate the MMC activity. Results showed that pig farm sludge was acclimated to the superior MMC with the maximum PHA content of 25% during the enrichment process with sludge retention time of 8 days. The structure of microbial communities in all treatments tended to be similar after 45 days’ enrichment, and the dominant bacteria were genus Paracoccus with abundance of 15.41–41.45%. The maximum dry cell weight, PHA content, and PHA yield of batch reactors using the superior MMC were 0.69 g/L, 36%, and 0.86 g PHA-COD/g COD, respectively. Dry cell weight concentrations reached 3.16 g/L in the PHA accumulation reactor with PHA content of 40–50% and PHA yield of 0.57 g PHA-COD/ g COD. The findings of this study provide an effective enrichment strategy for MMCs, which could improve the high efficiency synthesis of PHA from the fermentation broth of agricultural wastes and enhance the economy of PHA production at a marketable scale.

Polyhydroxyalkanoates production from lactic acid fermentation broth of agricultural waste without extra purification: The effect of concentrations

Polyhydroxyalkanoates (PHAs) production can potentially realize the high-value utilization of agricultural wastes and reduce the cost of commercial PHA production. This study aimed to explore the feasibility of converting lactic acid (LA) fermentation broth from agricultural wastes into PHAs. The LA fermentation broth from the co-fermentation of swine manure and apple waste and the simulated LA solution were used as feedstock. Effects of different LA concentrations of these feedstocks were explored in the PHA production. Results showed that PHA content and PHA yield of LA fermentation broth decreased with increase of concentrations of both feedstocks. The LA fermentation broth with LA concentration of 2420.8 mg/L resulted in the highest PHA content (55.4% dry cell weight) and PHA yield (0.48 g PHA-COD/g CODini). In addition, LA fermentation broth with LA concentration of 25084.5 mg/L had the highest concentration of PHA (1.04 g/L). The dominant bacteria for PHA production using both feedstocks were recognized as P. aminovorans. Using swine manure and apple waste to synthesize PHA could have the potential high benefits of economy and environment.

Comparison of ceramic microfiltration and ultrafiltration membranes for the clarification of simulated sebacic acid fermentation broth

Sebacic acid, an important chemical intermediate, is usually prepared by fermentation. However, the composition of the fermentation broth is complex, which causes significant difficulties in the purification of the product and is still a key problem in the industry. In this study, the application of ceramic membranes for the separation and purification of simulated fermentation broth was studied. Ceramic microfiltration (MF) and ultrafiltration (UF) membranes with average pore sizes of 100 and 6 nm, respectively, were systematically compared by analyzing their separation effects on different components in the fermentation broth and their permeation flux during filtration. Both ceramic MF and UF membranes can be used to clarify the fermentation broth with turbidity less than 0.01 NTU by the effective removal of emulsified oil and bacteria while allowing sodium sebacate to pass through freely. However, the ceramic UF membrane showed a higher protein rejection of more than 95%, whereas the removal rate of the MF membrane was only approximately 20%. In addition, the fouling process of ceramic UF membrane was analyzed. In the suitable operating conditions when the pH was 9.2, the temperature was 60 ℃, the pressure was 0.1 MPa and the cross-flow velocity was 1.8 m·s−1, the membrane fouling process was dominated by the reversible cake formation. A ceramic UF membrane with a smaller pore size can effectively avoid pollution in pore channels, and thus exhibits a higher permeation flux in the filtration of the fermentation broth.

Enhanced electrokinetic remediation by magnetic induction for the treatment of co-contaminated soil

The electroplating industry site is an important reservoir of per- and poly-fluoroalkyl substances (PFASs) and heavy metals. In this work, a novel electrokinetic in-situ chemical oxidation system was established to restore an actual soil co-contaminated with high concentrations of heavy metals (Cr, Cu, Zn and Ni) and PFASs. Potassium persulfate (PS, K2S2O8) and industrial waste steel slag were used as the oxidant and activator, respectively. The steel slag was evenly added in the soil, while PS was dosed in the cathode chamber. Citric acid fermentation broth produced by Aspergillus niger was added in the anode chamber to act as the metal chelator. A periodic alternating magnetic field was employed to enhance the catalytic performance of steel slag for PS. After 15-day treatment, 86.7% of PFASs and 87.2% of heavy metals were removed without PFASs accumulation in the electrolyte, with a defluorination percentage of 79.2%. The remediated soil had no phytotoxicity for wheat seed growth based on 7-day cultivation results. The quality of remediated soil could reach the national Class II criteria for residential use. Electron paramagnetic resonance spectroscopy analysis demonstrated that SO4•– and •OH were the major oxidative radicals responsible for PFASs degradation. Adding steel slag in the soil performed better than that in the cathode chamber based on pollutant removal and alleviating soil acidification. Magnetic induction could enhance PS activation by promote the corrosion of steel slag and thermal activation, thus increasing electrical current and electroosmotic flow, enhancing the transport of citric acid and PS, significantly improving the removal efficiency of heavy metals and PFASs.

Simultaneous and rate-coordinated conversion of lignocellulose derived glucose, xylose, arabinose, mannose, and galactose into D-lactic acid production facilitates D-lactide synthesis

D-lactide is the precursor of poly(D-lactide) (PDLA) or stereo-complex with poly(L-lactide) (PLLA). Lignocellulosic biomass provides the essential feedstock option to synthesize D-lactic acid and D-lactide. The residual sugars in D-lactic acid fermentation broth significantly blocks the D-lactide synthesis. This study showed a simultaneous and rate-coordinated conversion of lignocellulose derived glucose, xylose, arabinose, mannose, and galactose into D-lactic acid by adaptively evolved Pediococcus acidilactici ZY271 by simultaneous saccharification and co-fermentation (SSCF) of wheat straw. The produced D-lactic acid achieved minimum residual sugars (∼1.7 g/L), high chirality (∼99.1%) and high titer (∼128 g/L). A dry acid pretreatment eliminated the wastewater stream generation and the biodetoxification by fungus Amorphotheca resinae ZN1 removed the inhibitors from the pretreatment. The removal of the sugar residues and inhibitor impurities in D-lactic acid production from lignocellulose strongly facilitated the D-lactide synthesis. This study filled the gap in cellulosic D-lactide production from lignocellulose-derived D-lactic acid.

Construction and metabolic analysis of acetone-butanol-ethanol fermentation using mixed acetic acid and lactic acid in wastewater

To reuse organic acids in wastewater, efficient acetone-butanol-ethanol (ABE) fermentation was constructed using mixed acetic acid and lactic acid. The mixed acids were co-consumed with glucose, producing higher butanol concentration (6.96 g/L) and butanol yield (0.494 C-mol/C-mol) than using each single acid (6.22 g/L and 0.432 C-mol/C-mol). This result was verified by 13 C tracer experiment that addition of lactic acid improved carbon distribution to butanol instead of acetone , while acetic acid was readily consumed than lactic acid at initial fermentation stage. Subsequently, pH-stat fed batch fermentation at low pH of 5.5 further improved acid consumptions (6.34 g/L acetic acid and 9.06 g/L lactic acid) and solvent productions (12.4 g/L butanol and 6.50 g/L acetone). Finally, ABE fermentation using wastewater of lactic acid fermentation was performed without inhibition. Thus, efficient ABE fermentation can be implemented using mixed acetic acid and lactic acid, which is superior to using single acid. • This is the first study using mixed acetate and lactate for ABE fermentation. • 13 C experiment verified the metabolic flux to butanol was improved by the acids. • pH and glucose played an important role in acid consumption and solvent production. • Fermentation from lactic acid fermentation broth was performed without inhibition.

Fast monitoring the dynamic change of total acids during apple vinegar fermentation process using a colorimetric IDA sensor array

In this work, a colorimetric sensor array (CSA) for quantitative determination of total acids in apple vinegar during fermentation was constructed. The sensor array was properly designed based on indicators displacement assay (IDA) using three metal ions (Cu2+, Zn2+ and Ni2+) as receptors to organic acids. The time stability results showed that the prepared CSA had good operational stability. Three quantitative models, including one linear (partial least square, PLS) and two nonlinear (support vector regression, SVR and back propagation artificial neural network, BP-ANN) models were used to estimate the content of total acids in fermentation broth of apple vinegar through image analysis. The correlation coefficient (RP), root mean square error of prediction (RMSEP) and residual predictive deviation (RPD) of the better SVR model were 0.8708, 0.0545 and 10.91, respectively. The results implied that the CSA had an excellent potential for quantitative monitoring of total acids in apple vinegar during fermentation.

Portulaca oleracea Polysaccharides Modulate Intestinal Microflora in Aged Rats in vitro.

To explore the effect of Portulaca oleracea polysaccharides (POP) in regulating intestinal microflora in aged rats in vitro, its intestinal microbial composition was analyzed by 16 S rDNA high-throughput sequencing, and the level of short-chain fatty acids in fermentation broth was determined by LC-MS. POP significantly upregulated the relative abundance of Lactobacillus, Eggerthella, and Paraprevotella and significantly downregulated Escherichia_Shigella, Bacteroides, and Eubacterium nodatum groups. The pH value and ammonia nitrogen level decreased significantly in the POP-treated group, resulting in a more short-chain fatty acid consumption which changed the acid–base environment of the fermentation broth. In conclusion, POP is beneficial to aged rats because it can regulate intestinal flora, promote the growth of probiotics, and inhibit the reproduction of pathogenic bacteria.

Implementation of forward osmosis to concentrate alpha-ketoglutaric acid from fermentation broth: Performance and fouling analysis

Forward osmosis (FO) was demonstrated as a promising method to concentrate alpha-ketoglutaric acid in fermentation broth. Using a model solution containing alpha-ketoglutaric acid, the impact of the initial pH value on water flux, reverse salt flux, and rejection of alpha-ketoglutaric acid were first elucidated. Results from this study show that water flux was not affected by feed solution pH. However, feed solution pH could influence alpha-ketoglutaric acid rejection and reverse salt flux. The highest alpha-ketoglutaric acid rejection of 99.7% and lowest reverse salt flux were observed at pH 5. Multi-component model and real fermentation broth were then used to validate FO application for concentrating alpha-ketoglutaric acid. Water recovery of 80% was achieved without severe membrane fouling. In addition, membrane fouling analysis show that the built-up fouling layer of impurities is flaky and of unstable nature, suggesting that membrane fouling could be reversible. Knowledge of the fouling layer formation can contribute to the development of an effective method of pretreatment of the fermentation broth and cleaning FO membranes in the future.

Removal of heavy metals in municipal solid waste incineration fly ash using lactic acid fermentation broth.

Municipal solid waste incineration fly ash (MSWIFA) is considered as a hazardous solid waste because of the high mobility of heavy metals. In this study, the removal of heavy metals in MSWIFA using lactic acid fermentation broth (LAFB) under various leaching protocols (i.e. LAFB addition amount and timing) was investigated. Results revealed that compared with that in pure lactic acid solution, the synergistic effect of various substances in LAFB was more favourable to the dissolution of heavy metals. Although the content of acid-soluble heavy metals in MSWIFA decreased after leaching with LAFB, the leaching toxicity measured by acetic acid buffer solution method increased to varying degrees (except that of Cr). Moreover, the maximum leaching concentration of Pb was 14.1 mg/L (standard limit, 0.25 mg/L), which was not conducive to the landfill treatment of MSWIFA. However, if the LAFB-treated MSWIFA was used in cement kiln for co-disposal, the amount of MSWIFA entering the kiln was 6.0 percentage points higher than that in pure water leaching. Therefore, LAFB leaching instead of water leaching is expected to be an effective pre-treatment method for the utilisation of MSWIFA.

Chloride removal from municipal solid waste incineration fly ash using lactic acid fermentation broth.

As far as improvement of chlorine removal from fly ash by lactic acid fermentation broth (LAFB) was concerned, it is particularly important to explore the instinct mechanism and understand how leaching protocols (i.e. lactic acid addition amount and timing) affect the dechlorination efficiency. Results revealed that the WLL leaching protocol yielded the highest dechlorination efficiency (i.e. removed 98.7% of the total chlorine content of fly ash). The undissolved chlorine in fly ash residue might wrap inside the crystal structure of CaAlSiO4(OH). Given that the chlorine removal from fly ash might prohibit by the newly formed calcium salt precipitation, exclusively increase the addition amount of LAFB (i.e. LLL protocol) did not necessarily stimulate the dechlorination efficiency. Conversely, it might accelerate the fly ash mass reduction (compared with WLL protocol), resulting in a high chlorine content in fly ash residue. Therefore, instead of increasing lactic acid strength, reducing the thickness of the calcium salt precipitation layer or breaking the crystal structure of CaAlSiO4(OH) during the leaching process was suggested for efficient fly ash dechlorination.

Determination of citric and oxalic acid in fungi fermentation broth through HPLC-DAD and solid-phase extraction

This work describes a method for the simultaneous determination of organic acids in fungi fermentation broths. The sample preparation technique and the chromatographic conditions were optimized to enable the monitoring of the fermentation process. The determination of the citric and oxalic acid was done with a high resolution liquid chromatograph adapted to a detector with diode arrangement, an IC-Pak Ion-Exclusion 7μm (7.8 x 300 mm) column and a mobile phase of 0.001N H2SO4 with isocratic elusion. The validation parameters show efficiency, adequate linearity, and standard deviation values (%RSD) from 0.018% and 4.650%. the quantification limits (LDC) were 50.76 mg/L for citric acid and 20.18 mg/L for oxalic acid and the detection limits (LDD) were 0.6 mg/L for both acids. The method was applied in the analysis of organic acids in fermentation broths of Aspergillus niger.

Electrolyzing lactic acid in situ in fermentation broth to produce pyruvic acid in electrolysis cell.

Pyruvic acid is an important chemical in the carboxylate platform. Obstacles for its implementation are the need for high energy in chemical synthesis and additives in fermentation leading to increased production costs. Here, pyruvic acid generation from direct conversion of lactic acid in fermentation broth by electrolysis method is presented. It was found that lactic acid could be converted to pyruvic acid in the electrolysis cell under alkaline conditions. Using 12.53g/L lactic acid fermentation broth as anolyte, 7.01g/L pyruvic acid could be produced and productivity to lactic acid was 57.66% at initial pH11.74 and 5.0V applied a voltage in the electrolysis cell. Meanwhile, 0.472mol hydrogen was produced at the cathode. The electric energy efficiency was 76.18%. Lactic acid fermentation is relatively cheap and can be performed on many kinds of wastes and biomasses. The results suggest that pyruvic acid production from direct electrolysis of lactic acid fermentation broth can be economically feasible.

Degradation Kinetics of Clavulanic Acid in Fermentation Broths at Low Temperatures.

Clavulanic acid (CA) is a β-lactam antibiotic inhibitor of β-lactamase enzymes, which confers resistance to bacteria against several antibiotics. CA is produced in submerged cultures by the filamentous Gram-positive bacterium Streptomyces clavuligerus; yield and downstream process are compromised by a degradation phenomenon, which is not yet completely elucidated. In this contribution, a study of degradation kinetics of CA at low temperatures (−80, −20, 4, and 25 °C) and pH 6.8 in chemically-defined fermentation broths is presented. Samples of CA in the fermentation broths showed a fast decline of concentration during the first 5 h followed by a slower, but stable, reaction rate in the subsequent hours. A reversible-irreversible kinetic model was applied to explain the degradation rate of CA, its dependence on temperature and concentration. Kinetic parameters for the equilibrium and irreversible reactions were calculated and the proposed kinetic model was validated with experimental data of CA degradation ranging 16.3 mg/L to 127.0 mg/L. Degradation of the chromophore CA-imidazole, which is commonly used for quantifications by High Performance Liquid Chromatography, was also studied at 4 °C and 25 °C, showing a rapid rate of degradation according to irreversible first-order kinetics. A hydrolysis reaction mechanism is proposed as the cause of CA-imidazole loss in aqueous solutions.

Validation of spectrophotometric determination of chlorogenic acid in fermentation broth and fruits.

A fast and accurate ultraviolet-visible (UV-vis) spectrophotometric method was established to determine the presence of chlorogenic acid (CGA) according to potassium ferricyanide-Fe (III) detection system. The reaction temperature and pH level greatly influenced the CGA absorption spectrum. Maximum UV-vis absorption wavelength occurred at 790 nm under the optimum conditions (at 25 °C and pH 7.0). The results of UV-vis were further assessed by comparing the results with those of high-performance liquid chromatography (HPLC). The proposed method showed a wide linear sensing range of 10.0-800.0 μg mL-1 (R2 = 0.9996) and a high degree of precision (%R.S.D. < 1.50) and recovery (%R.S.D. > 3.39). Results of CGA and HPLC methods correlated well with each other. The proposed accurate, rapid, sensitive, low-cost, and high-throughput method was successfully used to quantify CGA in fermentation broth and fruits (Mango). Therefore, it may be applied for measuring CGA in biological samples.

Simultaneous decolorization and deproteinization of α,ω-dodecanedioic acid fermentation broth by integrated ultrafiltration and adsorption treatments.

α,ω-Dicarboxylic acids (DC) are versatile chemical intermediates with different chain length. For biosynthesis of DC, to obtain the highly pure product via crystallization, it is required to remove pigments and proteins in fermentation broth. However, a trade-off between decolorization/deproteinization ratio and DC recovery during the purification process was found, which impeded DC production by fermentation. When ultrafiltration (UF) was applied to treat α,ω-dodecanedioic acid (DC12) broth, 93.4% of DC12 recovery, 80.5% of decolorization ratio and 61.7% of deproteinization ratio were achieved by a PES 3 membrane. However, the membrane technology could not effectively retain the pigments or proteins with low molecular weight when a high DC12 permeation was required. Meanwhile, the selected activated charcoal or macroporous resins were not good adsorbents for the present system. Furthermore, an integrated process for decolorization and deproteinization was developed. After filtration with PES3 membrane, an activated charcoal was used to remove the small proteins and pigments in the UF permeate. As a result, 91.4% of DC12 recovery, 94.7% of decolorization ratio and 84.8% of deproteinization ratio were obtained by such two-stage strategy. These results would serve as a valuable guide for process design and practical operation in subsequent industrial application.

Study on the Stability of Poly-glutamic Acid Fermentation Broth for Agricultural Use

Poly-glutamic acid has been widely recognized in the field of agriculture as well as widely used in the field of medicine and cosmetics. However, because of its high cost and poor liquid stability, it has greatly restricted its application in agriculture. In this paper, poly-glutamic acid fermentation broth produced by Bacillus licheniformis A2-10 was fermented, and the liquid storage temperature, pH, and protective agents were optimized to enhance the stability of poly-glutamic acid fermentation broth. The preservation conditions of poly-glutamic acid are as follows: 20 °C, pH6.5, adding 2% urea, the viscosity of the fermentation liquid can be retained over 70% in 30 days, which is 10.67 times higher than that in the blank.

Compound washing remediation and response surface analysis of lead-contaminated soil in mining area by fermentation broth and saponin.

The development of eluent is the key to soil washing remediation, and a compound eluent was constructed using the prepared citric acid fermentation broth and saponin in this study. It displayed a good washing performance for Pb, Cu, Cr, and Cd in red soil, and the removal rates, especially Pb, gained an improvement compared with a single eluent. Based on this, the compound eluent was applied to remediation of Pb-contaminated soil in mining area; the desorption of Pb is a heterogeneous diffusion process, and Pb in large particle size soil is relatively easy to remove. An available response surface analysis model was established; its P < 0.0001 is very significant, and the P of the missing item is 0.1152. The degree of influence of three significant factors on removal of Pb is liquid-to-solid ratio > washing time > saponin concentration, and liquid-to-solid ratio and washing time show interaction. Moreover, the Pb removal rate can reach 56.20% under the optimized conditions: 0.25% saponin concentration, 20mL/g liquid-to-solid ratio, and 320-min washing time, which is close to the predicted value of 56.20% with a difference of 1.41%. In addition, most of the active Pb was removed and environmental risks were lowered after washing.