Acetic Acid Production by an Electrodialysis Fermentation Method with a Computerized Control System

In acetic acid fermentation by Acetobacter aceti, the acetic acid produced inhibits the production of acetic acid by this microorganism. To alleviate this inhibitory effect, we developed an electrodialysis fermentation method such that acetic acid is continuously removed from the broth. The fermentation unit has a computerized system for the control of the pH and the concentration of ethanol in the fermentation broth. The electrodialysis fermentation system resulted in improved cell growth and higher productivity over an extended period; the productivity exceeded that from non-pH-controlled fermentation. During electrodialysis fermentation in our system, 97.6 g of acetic acid was produced from 86.0 g of ethanol; the amount of acetic acid was about 2.4 times greater than that produced by non-pH-controlled fermentation (40.1 g of acetic acid produced from 33.8 g of ethanol). Maximum productivity of electrodialysis fermentation in our system was 2.13 g/h, a rate which was 1.35 times higher than that of non-pH-controlled fermentation (1.58 g/h).     

Growth conditions of clostridium perfringens type B for production of toxins used to obtain veterinary vaccines

The diseases caused for Clostridium perfringens are generically called enterotoxemias because toxins produced in the intestine may be absorbed into the general circulation. C. perfringens type B, grown in batch fermentation, produced toxins used to obtain veterinary vaccines. Glucose in concentrations of 1.4–111.1 mM was used to define the culture medium. The minimum concentration for a satisfactory production of vaccines against clostridial diseases was 55.6 mM. Best results were brought forth by meat and casein peptones, both in the concentration 5.0 g l^?1 in combination with glucose and a culture pH maintained at 6.5 throughout the fermentation process. The production of lactic, acetic and propionic organic acids was observed. Ethanol was the metabolite produced in the highest concentration when cultures maintained steady pH of 6.5 with exception of cultures with initial glucose concentration of 1.4 mM, where the highest production was of propionic acid. Maximal cell concentration and the highest toxin title concomitantly low yield coefficient to organic acids and ethanol were obtained using basal medium containing 111.1 mM glucose under a controlled pH culture (pH) 6.5 in batch fermentations of C. perfringens type B. These data contribute to improve process for industrial toxin production allowing better condition to produce a toxoid vaccine.     

Propionic Acid Production by a Propionic Acid-Tolerant Strain of Propionibacterium acidipropionici in Batch and Semicontinuous Fermentation

A propionic acid-tolerant derivative of Propionibacterium acidipropionici P9 was obtained by serially transferring strain P9 through broth that contained increasing amounts of propionic acid. After 1 year of repeated transfers, a strain (designed P200910) capable of growth at higher propionic acid concentrations than P9 was obtained. An increase in the proportion of cellular straight-chain fatty acids and uncoupling of propionic acid production from growth were observed for strain P200910. Growth rate, sugar utilization, and acid production were monitored during batch and semicontinuous fermentations of semidefined medium and during batch fermentation of whey permeate for both strain P200910 and strain P9. The highest propionic acid concentration (47 g/liter) was produced by P200910 in a semicontinuous fermentation. Strain P200910 produced a higher ratio of propionic acid to acetic acid, utilized sugar more efficiently, and produced more propionic acid per gram of biomass than did its parent in all fermentations.     

In vitro gas production kinetics and short-chain fatty acid production from rumen incubation of diets supplemented with hop cones (Humulus lupulus L.)

The aim of this study was to assess the effects of hop cones (Humulus lupulus L.) from two varieties Aurora and Dana, differing in their α- and β-acid contents, on rumen microbial activity measured with in vitro gas production kinetics and short-chain fatty acids (SCFA) production. Hop cones were added to the total mixed dairy cow ration (CONT) in concentrations simulating a cow’s daily intake of 50, 100 and 200 g of hop cones – the concentrations of hop cones expressed on a substrate basis were 43, 82 and 153 mg/g of substrate. Substrates were anaerobically incubated in glass syringes, and gas production kinetic parameters were determined by fitting data with the Gompertz model. Gas produced after 24 h (Gas24), maximum fermentation rate (MFR) and time of maximum fermentation rate (TMFR) were calculated from the estimated gas production kinetic parameters. After 24 h of incubation, the fermentation liquids of each substrate were taken for the determination of SCFA. Increasing the hop cone concentration decreased the total potential gas production, Gas24, MFR and shortened TMFR. The highest hop cone concentration significantly decreased acetic and butyric acid productions and total SCFA production after 24 h of incubation, but not propionic acid production, resulting in a decreased ratio between acetic acid and propionic acid.     

Isolation of an anaerobic cellulolytic mixed culture

Summary Isolation and enrichment cultures were made for anaerobic cellulose utilizing micro-organisms from non-ruminant sources. Stable mixed cultures were developed which degraded pure cellulose (wet-milled filter paper) in a defined mineral salts medium. Components of the mixed cultures lost viability in monoculture when grown on cellulose. Growth on cellulose was stimulated at low oxygen concentrations, when increased cellulase activity and increased volatile fatty acid production occurred.Low concentrations (0.1–3 mM) of cellobiose, and to a lesser extent, glucose stimulated solubilization of cellulose by the cultures, but higher concentrations had an inhibitory effect.Growth on cellulose was accompanied by production of acetic, propionic and butyric acids. The production and profile of the acids was stable and characteristic of the culture. When an open nonaseptic fermentation was employed, the fatty acid profile was variable and also included valeric acid.     

Propionic acid fermentation by Propionibacterium freudenreichii CCTCC M207015 in a multi-point fibrous-bed bioreactor

Propionic acid was produced in a multi-point fibrous-bed (MFB) bioreactor by Propionibacterium freudenreichii CCTCC M207015. The MFB bioreactor, comprising spiral cotton fiber packed in a modified 7.5-l bioreactor, was effective for cell-immobilized propionic acid production compared with conventional free cell fermentation. Batch fermentations at various glucose concentrations were investigated in the MFB bioreactor. Based on analysis of the time course of production, a fed-batch strategy was applied for propionic acid production. The maximum propionic acid concentration was 67.05 g l⁻¹ after 496 h of fermentation, and the proportion of propionic acid to total organic acids was approximately 78.28% (w/w). The MFB bioreactor exhibited excellent production stability during batch fermentation and the propionic acid productivity remained high after 78 days of fermentation.     

Propionic acid fermentation of lactose by Propionibacterium acidipropionici: effects of pH

Batch propionic acid fermentation of lactose by Propionibacterium acidipropionici were studied at various pH values ranging from 4.5 to 7.12. The optimum pH range for cell growth was between 6.0 and 7.1, where the specific growth rate was approximately 0.23 h(-1). The specific growth rate decreased with the pH in the acids have been identified as the two major fermentation products from lactose. The production of propionic acid was both growth and nongrowth associated, while acetic acid formation was closely associated with cell growth. The propionic acid yield increased with decreasing pH; It changed from approximately 33% (w/w) at pH 6.1-7.1 to approximately 63% at pH 4.5-5.0. In contrast, the acetic acid yield was not significantly affected by the pH; it remained within the range of 9%-12% at all pH values. Significant amounts of succinic and pyruvic acids were also formed during propionic acid fermentation of lactose. However, pyruvic acid was reconsumed and disappeared toward the end of the fermentation. The succinic acid yield generally decreased with the pH, from a high value of 17% at pH 7.0 to a low 8% at pH 5.0 Effects of growth nutrients present in yeast ex-tract on the fermentation were also studied. In general, the same trend of pH effects was found for fermentations with media containing 5 to 10 g/L yeast extract. However, More growth nutrients would be required for fermentations to be carried out efficienytly at acidic pH levels.     

Improvement in natamycin production by Streptomyces natalensis with the addition of short-chain carboxylic acids

Natamycin is an important tetraene (polyene) antibiotic produced in submerged culture by different strains of Streptomyces sp. In the present work, the effects of the addition of short-chain carboxylic acids (acetic, propionic and butyric) on cell growth and the kinetics of natamycin production were investigated during submerged cultivation of Streptomyces natalensis. The addition of acetic and propionic acids showed stimulatory effects on natamycin production when added to the fermentation medium at concentrations below 2 g L^?1 at the beginning of cultivation. In addition, when acetic and propionic acids were added in a mixture (7:1) at a total concentration of 2 g L^?1, antibiotic production increased significantly, reaching 3.0 g L^?1 (approximately 223% and 250% increases in volumetric and specific antibiotic production, respectively, compared with the control culture). Moreover, the addition of carboxylic acids not only increased the antibiotic yield but also decreased the production time from 96 h to only 84 h in shake-flask cultures. A further enhancement in natamycin production was achieved by cultivation in a 2-L stirred-tank bioreactor under controlled pH conditions. The maximum volumetric production of 3.98 g L^?1 was achieved after 84 h in carboxylic acid-supplemented culture (acetate and propionate in a ratio of 7:1).     

Effect in the cow of intraruminal infusions of volatile fatty acids and of lactic acid on the secretion of the component fatty acids of the milk fat and on the composition of blood

1. The effects in the cow of intraruminal infusions of acetic acid, propionic acid or butyric acid on the secretion of the component fatty acids of the milk fat, and of these acids and of lactic acid on the composition of the blood plasma of the jugular vein, have been studied. 2. The infusion of acetic acid or butyric acid increased the yield of the C₄–C₁₆ acids of milk fat but decreased the yield of C₁₈ acids. The infusion of propionic acid decreased the yields of all major component acids except palmitic acid and possibly lauric acid. 3. The changes in the concentrations in blood plasma of glucose and of ketone bodies were consistent with the glucogenic effect of propionic acid and the ketogenic effects of butyric acid and acetic acid. The effects of lactic acid were not consistent from cow to cow. Only with the infusion of acetic acid was a significant increase in the concentration of total volatile fatty acids in blood plasma found. Infusions of butyric acid and of propionic acid tended to depress the concentration of citric acid in the blood plasma and infusion of acetic acid increased it. No consistent effects of the infused acids on the concentration in blood plasma of esterified cholesterol, free cholesterol, triglyceride or phospholipid were observed. 4. The possibility is discussed that the effects of the infused acids on milk-fat secretion are caused through an alteration of the concentrations of precursors of milk fat in mammary arterial blood.     

Fed-batch fermentation with and without on-line extraction for propionic and acetic acid production byPropionibacterium acidipropionici

Fed-batch propionic and acetic acid fermentations were performed in semi-defined laboratory medium and in corn steep liquor withPropionibacterium acidipropionici strain P9. On average, over four experiments, 34.5 g/l propionic acid and 12.8 g/l acetic acid were obtained in about 146 h in laboratory medium with 79 g/l glucose added over five feeding periods. The highest concentration of propionic acid, 45 g/l, was obtained when the glucose concentration was not allowed to drop to zero. In corn steep liquor 35 g/l propionic acid and 11 g/l acetic acid were produced in 108 h from 59.4 g/l total lactic acid provided as seven feedings of corn steep liquor. Extractive fed-batch fermentations were conducted in semi-defined medium using either flat-sheet-supported liquid membranes or hollow-fiber membrane extraction to remove organic acids from the culture medium. As operated during the course of the fermentation, these systems extracted 25% and 22% of the acetic acid and 36.5% and 44.5% of the propionic acid, respectively, produced in the fermentation. Total amounts of acids produced were about the same as in comparable nonextractive fermentations: 30–37 g/l propionic acid and 13 g/l acetic acid were produced in 150 h. Limitations on acid production can be attributed to limited substrate feed, not to failure of the extraction system.Journal paper J-16303 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project 3122.     

反相高效液相色谱法测定肠球菌FQ15发酵液中的有机酸

目的研究肠球菌FQ15发酵液中的有机酸在不同发酵时间的变化趋势。方法建立反相高效液相色谱法测定此株益生菌发酵液中有机酸的主要成分及其在发酵不同时间的变化趋势。结果丙酸、丙酮酸、乳酸、乙酸的浓度都是在菌体生长处于衰亡期时达到最大值,乳酸随发酵时间的延长浓度明显下降,而乙酸在发酵后期含量呈上升趋势。结论此方法重现性好,精密度高,为研究微生物合成中有机酸种类及变化趋势提供了一种可供参考的快捷分析手段。     

Monensin and dichloroacetamide influences on methane and volatile Fatty Acid production by rumen bacteria in vitro

The effect of monensin (0 or 33 mug/g of diet) upon rumen fermentation in the presence and absence of methanogenesis was determined in vitro by using mixed rumen organisms continuously cultured for 17 days. Methane was inhibited by dichloroacetamide (DCA; 32 mg/day) or by a pH of 5.1. Monensin effected a significant decrease in the ratio of acetic to propionic acid in the presence or absence of methanogenesis. In the absence of methanogenesis, the decrease in the ratio of acetic to propionic acid was entirely the result of increased propionic acid, whereas in the presence of methanogenesis the decrease in the ratio was the result of a combination of decreased acetic acid and increased propionic acid. There was a complementary interaction between monensin and DCA on volatile fatty acid production (expressed as millimoles of carbon per day). Addition of monensin to DCA-treated cultures resulted in the production of more acid; however, monensin and DCA had no beneficial effect on total carbon formed as acid and gases as compared with nonsupplemented control cultures. The monensin and DCA also resulted in greater digestion of neutral detergent fiber and less accumulation of formic acid and hydrogen as end products than did DCA alone. l-Lactic acid was produced in small but significantly greater amounts by the low-pH cultures, which also had less volatile fatty acid carbon formed from the fiber fraction of the forage supplied.     

Propionibacterium acidipropionici CRL1198 influences the production of acids and the growth of bacterial genera stimulated by inulin in a murine model of cecal slurries

Different attempts have been made to improve the health status of humans and animals by increasing the intestinal production of short-chain fatty acids (SCFA) derived from non-digestible carbohydrates fermentation. In this paper we investigate the in vitro production of short-chain fatty acids (SCFA) after addition of inulin, propionibacteria or a combination of both in an experimental model of mice cecal slurries. The development of bacterial genera which are usually stimulated by inulin addition was also investigated. According to our experimental data, acetic acid and butyric acids concentrations increased after incubation in slurries that had no supplements. By contrast, butyric acid concentrations remained in the basal value when supplements were used. Fermentation of only inulin did not increase the concentration of total SCFA. Propionibacterium acidipropionici CRL1198 improved the production of propionic acid in cecal slurries when it was added alone, but the effect was more noticeable in the combination with inulin. A modulation of the global fermentative activity of the cecal microbiota was evidenced by the increase on the ratio propionic acid/SCFA in supplementations with propionibacteria. Statistical analysis of data demonstrated that samples from homogenates with propionibacteria alone or combined with inulin belong to the same cluster. The presence of propionibacteria limited the growth of Bacteroides fragilis and Clostridium hystoliticum groups in slurries with and without inulin. The growth of Bifidobacterium was not modified and the stimulating effect of inulin on lactobacilli disappeared in the presence of propionibacteria. In conclusion, dairy propionibacteria are potential candidates to develop new functional foods helpful to ensure the intestinal production of SCFA during inulin supplementation and to control the overgrowth of bacteria belonging to Bacteroides and Clostridium genera.     

Characterization of anaerobic microbial culture with high acidogenic activity

The mixed cultures which were used were isolated from municipal sludge digesters, and the production of organic acids (acetic, propionic, butyric, etc.) from carbohydrates was tested. The behavior of the reference population (culture R) obtained directly from the sewage treatment plant, is compared to that obtained after three months in a plug-flow reactor (Gradostat fermentor) without pH control (culture A) and after six months with pH control (culture B). For culture B, the specific rate of acid production is related to the cell growth rate by (1/X)r_p= 17 µ + 1.6 with a maximal acid concentration of 40 g/liter. The batch culture yields are improved from 0.36g/g for the initial culture (R) to 0.72 g/g for culture B after six months in continuous culture, and 0.8 g/g in plug-flow continuous culture. The productivity of organic acids reaches 1.7 g/liter·hr. It is suggested that the acidogenic fermentation, the first step of methanogenesis, is a potential process to produce acetic, propionic, and butyric acids.     

The effects of cell recycling on the production of 1,3-propanediol by Klebsiella pneumoniae

The effects of both biomass age and cell recycling on the 1,3-propanediol (1,3-PDO) production by Klebsiella pneumoniae were investigated in a membrane-supported bioreactor using hollow-fiber ultrafiltration membrane module in two separate experiments. It was determined that older cells have a negative effect on 1,3-PDO production. The concentrations of by-products, such as acetic acid and ethanol, increased in cultures with older cells, whereas the concentrations of succinic acid, lactic acid and 2,3-butanediol decreased. The effect of cell recycling was comparatively studied at a cell recycling ratio of 100 %. The results showed that cell recycling had also negative effects on 1,3-PDO fermentation. It was hypothesized that both cell recycling and biomass age caused metabolic shifts to undesired by-products which then inhibited the 1,3-PDO production. On the other hand, the use of hollow-fiber ultrafiltration membrane module was found to be very effective in terms of removal of cells from the fermentation broth.     

Whey fermentation by immobilized cells of Propionibacterium shermanii

Growth of Propionibacterium shermanii B-123 was faster on media containing lactate than on that containing lactose. Cheese whey was therefore fermented with Lactobacillus helveticus and neutralized with NaOH or Ca(OH)₂, before inoculation with B-123. Fermentation rate by immobilized propionibacteria was best in Ca(OH)₂-neutralized whey, and at lactate concentrations between 1 and 2%. Calcium propionate concentrations of 1 and 3% reduced fermentation rates by 40% and 55% respectively. Optimum temperature for propionate fermentation by immobilized cells was 37°C. Ratios of propionic acid to acetic acid increased as incubation temperature was increased. Agitation increased propionic acid fermentation rates but lowered the ratio of propionic acid to acetic acid. Beads containing immobilized propionibacteria were re-utilized for ten consecutive fermentations. Fermentation rates increased upon re-utilization. Escherichia coli and Staphylococcus aureus were inhibited by the propionic fermentation but did not die; they kept growing at a reduced rate.     

Inhibitory Effects of Turf Pesticides on Bacillus popilliae and the Prevalence of Milky Disease

Fourteen pesticides (fungicides, herbicides, and insecticides) were tested to determine whether they had deleterious effects on the bioinsecticide Bacillus popilliae, the causal agent of milky disease. All of these pesticides reduced levels of spore viability, spore germination, and/or vegetative cell growth when they were tested over a range of concentrations from 0 to 1,000 ppm of active ingredient, and the fungicides had the greatest detrimental effects. As determined by tests in water, the level of spore viability was significantly reduced by chlorothalonil, iprodione, (2,4-dichlorophenoxy)acetic acid plus 2-(2,4-dichlorophenoxy)propionic acid, and 2-[(4-chloro-o-tolyl)oxy]propionic acid plus (2,4-dichlorophenoxy)acetic acid. In tests performed with iprodione, loss of viability was evident at concentrations less than the concentration calculated to result from recommended use. Tests performed in soil demonstrated that triadimefon, chlorothalonil, (2,4-dichlorophenoxy)acetic acid plus 2-(2,4-dichlorophenoxy)propionic acid, and pendimethalin at concentrations resulting from recommended rates of application reduced spore titers. Spore germination did not occur in the continued presence of 2-[(4-chloro-otolyl)oxy]propionic acid plus (2,4-dichlorophenoxy)acetic acid, isofenphos, and chlordane, whereas exposure of spores to triadimefon or pendimethalin for 2 days stimulated germination. The tests to determine effects on spore germination were inconclusive for all other pesticides. Triadimefon, chlorothalonil, iprodione, pendimethalin, and chlorpyrifos at concentrations less than the concentrations recommended for use inhibited vegetative cell growth of B. popilliae, and chlordane at a concentration that was twice the concentration expected to result from the recommended rate of application repressed cell growth. My data support the hypothesis that use of synthetic pesticides can contribute to a low incidence of milky disease in white grubs.     

Production of carboxylic acids from hydrolyzed corn meal by immobilized cell fermentation in a fibrous-bed bioreactor

Corn meal hydrolyzed with amylases was used as the carbon source for producing acetic, propionic, and butyric acids via anaerobic fermentations. In this study, corn meal, containing 75% (w/w) starch, 20% (w/w) fibers, and 1.5% (w/w) protein, was first hydrolyzed using amylases at 60 degrees C. The hydrolysis yielded approximately 100% recovery of starch converted to glucose and 17.9% recovery of protein. The resulting corn meal hydrolyzate was then used, after sterilization, for fermentation studies. A co-culture of Lactococcus lactis and Clostridium formicoaceticum was used to produce acetic acid from glucose. Propionibacterium acidipropionici was used for propionic acid fermentation, and Clostridium tyrobutylicum was used for butyric acid production. These cells were immobilized on a spirally wound fibrous matrix packed in a fibrous-bed bioreactor (FBB) developed for multi-phase biological reactions or fermentation. The bioreactor was connected to a stirred-tank fermentor that provided pH and temperature controls via medium circulation. The fermentation system was operated at the recycle batch mode. Temperature and pH were controlled at 37 degrees C and 7.6, respectively, for acetic acid fermentation, 32 degrees C and 6.0, respectively, for propionic acid fermentation, and 37 degrees C and 6.0, respectively, for butyric acid production. The fermentation demonstrated a yield of approximately 100% and a volumetric productivity of approximately 1 g/(1 h) for acetic acid production. The propionic acid fermentation achieved an approximately 60% yield and a productivity of 2.12 g/(1 h), whereas the butyric acid fermentation obtained an approximately 50% yield and a productivity of 6.78 g/(1 h). These results were comparable to, or better than those fermentations using chemically defined media containing glucose as the substrate, suggesting that these carboxylic acids can be efficiently produced from direct fermentation of corn meal hydrolyzate. The corn fiber present as suspended solids in the corn meal hydrolyzate did not cause operating problem to the immobilized cell bioreactor as is usually encountered by conventional immobilized cell bioreactor systems. It is concluded that the FBB technology is suitable for producing value-added biochemicals directly from agricultural residues or commodities such as corn meal.     

The influence of LBG addition to carrageenan on the mechanical stability of the gel and the fermentative activity of immobilized propionic acid bacteria

In the first part of the experiments, the mechanical properties of 1%, 2% and 3% carrageenan and 1%, 2% and 3% carrageenan/locust bean gum (LBG) gels stored in various concentrations of propionic and acetic acids and their mixtures were examined. The stability of these materials was measured by uniaxial compression between two parallel plates using the Instron Universal Testing Machine. A mathematical model explaining the dependence of the destroying force on the storage time was chosen for data analysis. Using this model, the average rate of gel deterioration was calculated. The structural properties of the examined gels were most influenced by the highest concentration of propionic and acetic acids and their mixtures (1% acetic acid and 2% propionic acid). The addition of LBG to carrageenan decreased the gel destroying force and increased its resistance to acids. In the second part of the experiments, the Propionibacterium freudenreichii subsp. shermanii NCFB 1081 and NCFB 566 were immobilized in a living state in 1%, 2% and 3% carrageenan and 1%, 2% and 3% carrageenan/LBG gels. The ammonia consumption, glucose utilization, production of propionic and acetic acids and the biosynthesis of vitamin B₁₂ were examined. An increase in the productivity of propionic acid and a significant decrease in the vitamin B₁₂ produced in the biosynthesis were observed when immobilized cells were used. The immobilization of cells enhanced the productivity of propionic acid by up to 40% compared to free cells. The best results were obtained for the second and third applications of immobilized cells in all concentrations of carrageenan gels and 2% and 3% carrageenan/LBG gels The results showed that carrageenan/LBG is a better support material for the immobilization of propionic acid bacteria than the pure carrageenan.     

High-Level Production of Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) by Fed-Batch Culture of Recombinant Escherichia coli

Fermentation strategies for production of high concentrations of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] with different 3-hydroxyvalerate (3HV) fractions by recombinant Escherichia coli harboring the Alcaligenes latus polyhydroxyalkanoate biosynthesis genes were developed. Fed-batch cultures of recombinant E. coli with the pH-stat feeding strategy facilitated production of high concentrations and high contents of P(3HB-co-3HV) in a chemically defined medium. When a feeding solution was added in order to increase the glucose and propionic acid concentrations to 20 g/liter and 20 mM, respectively, after each feeding, a cell dry weight of 120.3 g/liter and a relatively low P(3HB-co-3HV) content, 42.5 wt%, were obtained. Accumulation of a high residual concentration of propionic acid in the medium was the reason for the low P(3HB-co-3HV) content. An acetic acid induction strategy was used to stimulate the uptake and utilization of propionic acid. When a fed-batch culture and this strategy were used, we obtained a cell concentration, a P(3HB-co-3HV) concentration, a P(3HB-co-3HV) content, and a 3HV fraction of 141.9 g/liter, 88.1 g/liter, 62.1 wt%, and 15.3 mol%, respectively. When an improved nutrient feeding strategy, acetic acid induction, and oleic acid supplementation were used, we obtained a cell concentration, a P(3HB-co-3HV) concentration, a P(3HB-co-3HV) content, and a 3HV fraction of 203.1 g/liter, 158.8 g/liter, 78.2 wt%, and 10.6 mol%, respectively; this resulted in a high level of productivity, 2.88 g of P(3HB-co-3HV)/liter-h.