Production of L‐lactic acid with very high gravity distillery wastewater from ethanol fermentation by a newly isolated Enterococcus hawaiiensis

BACKGROUND: A great amount of wastewater with high contents of chemical oxygen demand (COD) are produced by ethanol production. It would be useful to utilize distillery wastewater to produce L‐lactic acid, which could be a high additional value byproduct of ethanol production. The fermentation process of L‐lactic acid production by a newly isolated Enterococcus hawaiiensis CICIM‐CU B0114 is reported for the first time. RESULTS: The strain produced 56 g L^?1 of L‐lactic acid after cultivation for 48 h in optimized medium consisting of (g L^?1) 80 glucose, 10 peptone, 10 yeast extract, 1.5 Na₂HPO₄ and 0.2 MgSO₄. E. hawaiiensis CICIM‐CU B0114 was isolated and purified by subculture for growing and producing L‐lactic acid in distillery wastewater of very high gravity (VHG) from ethanol fermentation. L‐lactic acid fermentation was further studied with distillery wastewater substrate in 7 L and 15 L fermentors. The results showed that L‐lactic acid concentrations of 52 g L^?1 and 68 g L^?1 was achieved in 7 L and 15 L fermentors with the initial sugar concentrations of 67 g L^?1 and 87 g L^?1, respectively. CONCLUSION: The production of L‐lactic acid by the newly isolated E. hawaiiensis CICIM‐CU B0114 was carried out and the fermentation medium was optimized by orthogonal experimental design. This new strain holds the promise of L‐lactic acid production utilizing distillery wastewater from VHG ethanol fermentation. Copyright © 2010 Society of Chemical Industry     

Optimization of medium for phenylalanine ammonia lyase production in <Emphasis Type="Italic">E. coli</Emphasis> using response surface methodology

A culture medium for phenylalanine ammonia lyase (PAL) production in E. coli was developed following preliminary studies by means of response surface methodology (RSM). The medium components having significant effect on the production were first identified by using a fractional factorial design. Then, central composite design (CCD) was used to optimize the medium constituents and explain the combined effects of four medium constituents: glucose, yeast extract, (NH₄)₂HPO₄ and MgSO₄. A quadratic model was found to fit the PAL production. CCD revealed that the optimum values of the test variables for PAL production were glucose 28.2 g/L, yeast extract 5.01 g/L, (NH₄)₂HPO₄ 7.02 g/L and MgSO₄ 1.5 g/L. PAL production of 62.85 U/g, which was in agreement with the prediction, was observed in the verification experiment. In comparison to the production of basal medium, 1.8-fold increase was obtained.     

Application of statistical experimental design for optimization of physiological factors and their influences on production of pullulan by <Emphasis Type="Italic">Aureobasidium pullulans</Emphasis> HP-2001 using an orthogonal array method

Physiological factors for the production of pullulan by A. pullulans HP-2001 were optimized using orthogonal array method and their influences were compared using Qualitek-4 software. The analysis of variance (ANOVA) indicated that the most important factor for cell growth was yeast extract, whereas that for production of pullulan was glucose. The optimal conditions for cell growth were found to be 100.0 g/L glucose, 10.0 g/L yeast extract, and initial pH of 6.0, whereas those for the production of pullulan were 100.0 g/L glucose, 2.5 g/L yeast extract, and initial pH of 5.5. Among four mineral salts in the medium, potassium phosphate (K₂HPO₄) was found to be the most important factor for cell growth as well as production of pullulan. Next important salt for cell growth was (NH₄)₂SO₄, whereas that for production of pullulan was NaCl. The optimal concentrations of K₂HPO₄, NaCl, MgSO₄·7H₂O, and (NH₄)₂SO₄ for cell growth were 7.5, 1.00, 0.1, and 1.20 g/L, respectively, whereas those for production of pullulan were 2.5, 0.25, 0.8, and 0.30 g/L. The expected cell growth and the production of pullulan by A. pullulans HP-2001 under these optimized conditions were 12.61 and 11.49 g/L, respectively.     

Batch production of L(+) lactic acid from whey by Lactobacillus casei (NRRL B‐441)

The effects of temperature, pH, and medium composition on lactic acid production by Lactobacillus casei were investigated. The highest lactic acid productivity values were obtained at 37 °C and pH 5.5. The productivity was 1.87 g dm^?3 h^?1 at 37 °C in shake flasks. In the fermenter, a productivity of 3.97 g dm^?3 h^?1 was obtained at pH 5.5. The most appropriate yeast extract concentration was 5.0 g dm^?3. Whey yielded a higher productivity value than the analytical lactose and glucose. Initial whey lactose concentration did not affect lactic acid productivity. MnSO₄ ·H₂O was necessary for lactic acid production by L casei from whey. Product yields were approximately 0.93 g lactic acid g lactose^?1. Copyright © 2004 Society of Chemical Industry     

Different combinations of salts affect the growth and bacteriocin production by Lactobacillus salivarius CRL 1328

BACKGROUND: The culture medium for optimal growth of vaginal Lactobacillus salivarius CRL 1328 is different from that for optimal bacteriocin production. To simultaneously obtain high amount of biomass and bacteriocin of this microorganism, the effects of different basal culture media and salts on both responses were evaluated. The study was performed by using a complete factorial experimental design 2⁶, with central points. Sixty‐four different growth media, which resulted from the combinations of two basal culture media and two concentrations of five salts (ammonium citrate, sodium acetate, MgSO₄, MnSO₄, and K₂HPO₄) were assayed. RESULTS: Only the addition of MnSO₄ to each culture medium significantly stimulated the growth of L. salivarius. The presence of sodium acetate or MgSO₄ stimulated the bacteriocin production, while MnSO₄ and K₂HPO₄ exerted an inhibitory effect. However, the simultaneous addition of MnSO₄ and sodium acetate to both basal culture media allowed high bacteriocin levels to be reached, attenuating the inhibitory effect of Mn²⁺. CONCLUSIONS: The application of a complete experimental design contributed to simultaneous optimization of the biomass and bacteriocin production of L. salivarius CRL 1328. The results obtained are potentially applicable to the technological production of probiotic bacteria and antagonistic substance to be included in a probiotic pharmaceutical product. Copyright © 2009 Society of Chemical Industry     

Development of biosensor for phenol detection using agarose–guar gum based laccases extracted from Pleurotus ostreatus

Laccases from Pleurotus ostreatus was extracted from the Shaken flask cultures of Pleurotus ostreatus grown at 25°C with continuous agitation (110 rpm.) in baffled 1000 mL Erlenmeyer flasks containing 200 mL medium. The basal GYP medium used for cultures contained 20 g glucose l^?1, 5 g yeast extract l^?1, 5 g peptone from casein l^?1, and 1 g MgSO₄.7H₂O l^?1. The pH was adjusted to 5.0 with H₃PO₄ before sterilization. The kinetics of oxidation reactions catalyzed by laccases was studied using 2,2′‐azino‐bis (3‐ethylbenzthiazoline‐6‐sulphonic acid). The laccases showed lower specific activity and higher activity in nonpolar organic solvents. A biosensor using laccases was constructed for the determination of phenol. The enzyme was extracted from Pleurotus ostreatus and entrapped in agarose–guar gum composite biopolymer matrix. Phenol was determined by direct reduction of biocatalytically liberated quinone species at ?0.1 V versus Ag/AgCl (3M KCl). The response was found to be linear and concentration dependent.It has a shelf life of more than 2 months when stored at 4°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Improvement of Staphylococcus xylosus lipase production through optimization of the culture conditions

The Staphylococcus xylosus strain produces without induction an original lipase named S. xylosus lipase (SXL). Since considerable interest has been given to microbial lipases for biotechnology applications like detergents, food, drugs and pharmaceutical products, improvement of their production is of great importance to reduce the final cost. This goal could be reached through the optimization of several physicochemical culture conditions. Indeed, an appropriate medium was formulated for SXL production. It was composed of 17 g/L pancreatic digest of casein, 2.5 g/L glucose, 6 g/L yeast extract, 0.75 g/L ammonium sulfate corresponding to a C/N ratio of 6, 1 g/L K₂HPO₄ and 1 g/L KH₂PO₄. In such a medium, SXL production reached 42 U/mL. Moreover, the usefulness of such a medium for large‐scale production of SXL was also evidenced in an automated fully controlled 2.6‐L fermenter. It was shown that aeration of the medium, which strongly affected the growth, regulated the lipase synthesis by the produced cells. It was found that when using a dissolved oxygen saturation of the medium of 50%, the SXL production reached 62 U/mL.     

Statistical optimization of fermentation conditions for the improved production of poly-β-hydroxybutyrate from Bacillus subtilis

Poly-β-hydroxybutyrate (PHB) has been an effective biodegradable plastic obtained by microbial fermentation. Batch fermentation of Bacillus subtilis features an attractive system for the production of PHB. Identification of appropriate media components and cultivation conditions are extremely important for the optimal production of biomass and/or PHB production. Statistical media design was utilized for the optimization of different fermentation variables (glucose, peptone, sodium chloride, K₂HPO₄, KH₂PO₄, ammonium sulfate, ammonium chloride, sodium sulfate, temperature, inoculum size, and pH). The optimized media predicted the optimal dry cell weight of 7.54?g?L^?1 and PHB production of 77.2?mg?L^?1 at 1?g?L^?1 of peptone, 1.46?g?L^?1 sodium sulfate, and pH 6.8 in 24?h. Glucose utilization, batch growth, and PHB production kinetics of B. subtilis were determined experimentally. The effect of substrate inhibition on specific growth rate was also determined experimentally for B. subtilis. The values of kinetic and substrate inhibition parameters obtained from this study shall be utilized to develop a mathematical model for PHB production for further improving the production of PHB.     

Modeling and optimization of cutinase production by recombinant Escherichia coli based on statistical experimental designs

Statistics-based experiment designs were used to optimize the culture medium (glucose, yeast extract, IPTG, tween-60, and CaCl₂) for cutinase production by recombinant Escherichia coli. A 2^5-1 fractional factorial design augmented with center points revealed that glucose, yeast extract, and IPTG were the most significant factors, whereas the other factors were not important within the levels tested. The method of steepest ascent was used to approach the proximity of optimum, followed by a central composite design to develop a response surface for culture condition optimization. The optimum culture medium for cutinase production was found to be: glucose 33. 92 g/L, yeast extract 30.92 g/L, and IPTG 0.76 g/L. A cutinase production of 145.27±1.5 U/mL, which was in agreement with the prediction, was observed in triplicate verification experiments. The results obtained here verified the effectiveness of the applied methodology and may be helpful for cutinase production on an industrial scale.     

Optimization of α‐amylase production in solid substrate fermentation

Response surface methodology (RSM) was used to optimize the medium components of α‐amylase production using solid substrate fermentation (SSF). Hazelnut cake (HC), peptone, yeast extract (YE), and (NH₄)₂SO₄ were selected as independent variables for optimization. Central composite design (CCD) was used in design experiments and analysis results. This procedure limited the number of actual experiments performed while allowing possible interactions between the independent variables. By using CCD, 30 experiments were performed for determining the interaction of independent variables and optimization of fermentation medium. The P‐value of the coefficient of linear effect of (NH₄)₂SO₄ concentrations, which was obtained as 0.0001 has shown that this parameter has the greatest effect on the production of α‐amylase. Model F‐value (5.62) implies that the model is significant. The highest α‐amylase activity (4895 IU) was measured when the HC, peptone, YE, and (NH₄)₂SO₄ concentrations in the medium were 22.62, 5.20, 1.62, and 6.81 g L^?1, respectively.     

虎奶菇菌丝体胞外多糖深层发酵培养基的优化

研究了营养性因子对虎奶菇菌丝体深层发酵的影响,结果表明蔗糖、马铃薯、蛋白胨和酵母膏有利于胞外多糖的形成。进一步的正交优化实验确定了虎奶菇多糖深层发酵的最佳培养基组成(g/L)为∶蔗糖2 g/100 mL,马铃薯25 g/100 mL,蛋白胨0.2 g/100 mL,酵母膏0.2 g/100 mL。     

Optimization of extracellular lipase production by Debaryomyces hansenii isolates from dry-salted olives using response surface methodology

The lipase production by Debaryomyces hansenii strains isolated from dry-salted olives cv. Thassos was investigated. Glucose, olive oil and pH were essential to obtain a high lipase yield. Optimization of the medium components which enhance lipase production by the strain D. hansenii YLL29 was achieved with the aid of response surface methodology. The composition of the optimized medium to enhance lipase production by D. hansenii is as follows (g/L): yeast extract 5.0, peptone 10, K₂HPO₄ 4.0, MgSO₄·7H₂O 1.0, glucose 13.1, olive oil 19, Tween 80 3.8, and pH 6.4. Practical validation of the optimum medium gave lipase activity 7.44 U/mL, which was 2.28-fold higher than the unoptimized conditions. Under the optimized conditions the twenty D. hansenii isolates showed increased lipase activity fluctuating between 6.00 and 7.44 U/mL. The results corroborated the validity and the effectiveness of the model, as the statistical approaches proved to be suitable in predicting the optimum production medium composition for maximum extracellular lipase yield. The high lipolytic activity of D. hansenii YLL29 (7.44 U/mL) indicates the possible commercial importance of this isolate.     

Optimization of growth medium for the production of α‐amylase from Bacillus amyloliquefaciens using response surface methodology

The optimization of nutrient levels for the production of α‐amylase by Bacillus amyloliquefaciens was carried out using response surface methodology (RSM) based on the 2³ factorial central composite design (CCD). This procedure limited the number of actual experiments performed while allowing for possible interactions between three components. RSM was adopted to derive a statistical model for the effect of starch, peptone and yeast extract (YE) on α‐amylase production. The P‐value of the coefficient for linear effects of starch and YE concentration was <0.0001, suggesting that this was the principal experimental variable, having the greatest effect on the production of α‐amylase. The optimal combinations of media constituents for maximum α‐amylase production were determined as 12.61 g L^?1 starch, 2.83 g L^?1 peptone and 1.25 g L^?1 YE. The optimization of the medium resulted not only in a 34% higher enzyme activity than unoptimized medium but also in a reduced amount of the required medium constituents. Copyright © 2006 Society of Chemical Industry     

乳链菌肽发酵的主要影响因子

采用中心组合实验设计方法（ＣｅｎｔｒａｌＣｏｍｐｏｓｉｔｅＤｅｓｉｇｎ）,运用ＳＡＳ统计分析软件,得到了乳链菌肽发酵单位与主要影响因子之间的回归方程：ＹＩＵ＝１０８７．１７＋６２．８６Ｘ１＋７６．１８Ｘ２＋５５．４１Ｘ４－２３．３５Ｘ１１．６２Ｘ－１５．６７Ｘ２Ｘ４．根据方程及其岭岭分析结果,设计出含氮量较低的培养基ＳＹＳ３．同ＣＭ培养基相比,原料成本相差不大,但发酵单位提高了６４％．同ＭＲＳ培养基相比,虽然氮源含量降低了约５０％;发酵水平却相当,同时发酵液中残留的杂蛋白减少可以降低杂蛋白对Ｎｉｓｉｎ提取的干扰作用．     

Utilization of response surface methodology to optimize the culture media for the production of rhamnolipids by Pseudomonas aeruginosa AT10

Pseudomonas aeruginosa AT10 produced a mixture of surface‐active rhamnolipids when cultivated on mineral medium with waste free fatty acids as carbon source. The development of the production process to an industrial scale included the design of the culture medium. A 2⁴ full factorial, central composite rotational design and response surface modelling method (RSM) was used to enhance rhamnolipid production by Pseudomonas aeruginosa AT10. The components that are critical for the process medium were the carbon source, the nitrogen source (NaNO₃), the phosphate content (K₂ HPO₄/KH₂PO₄ 2:1) and the iron content (FeSO₄·7H₂O). Two responses were measured, biomass and rhamnolipid production. The maximum biomass obtained was 12.06 g dm^?3 DCW, when the medium contained 50 g dm^?3 carbon source, 9 g dm^?3 NaNO₃, 7 g dm^?3 phosphate and 13.7 mg dm^?3 FeSO₄·7H₂O. The maximum concentration of rhamnolipid, 18.7 g dm^?3, was attained in medium that contained 50 g dm^?3 carbon source, 4.6 g dm^?3 NaNO₃, 1 g dm^?3 phosphate and 7.4 mg dm^?3 FeSO₄·7H₂O. © 2002 Society of Chemical Industry     

Fermentative production of puromycin by Streptomyces alboniger

Two strains of Streptomyces alboniger NRRL B-1832 and 2403 were used for the biosynthesis and production of puromycin using different media. Streptomyces alboniger NRRL B-2403 produced more puromycin than NRRL B-1832 on medium composed of (amounts in g/1), soybean meal 10.0; corn steep 20.0; dextrin 10.0; NaCl 5.0; CaCO₃ 2.0, and K₂HPO₄ 2.0. When the carbon and nitrogen sources of the basal medium were replaced by different carbon and nitrogen sources it was found that dextrin, sucrose, starch and maltose favoured the production of higher titres of puromycin, while generally organic nitrogen sources such as soybean meal and fodder yeast (40.0 and 50.0% total nitrogen) stimulated puromycin yield. On the evidence of their chemical compositions and because they are cheap and produced locally Egyptian black, strap molasses and fodder yeast are preferably used in medium for the production of puromycin. The other conditions favouring and controlling the production and biosynthesis of puromycin by fermentation were investigated.     

2-Hydroxyhexadecanoic and 8,9,13-trihydroxydocosanoic acid accumulation by yeasts treated with fumonisin B1

Fumonisin B₁ is a sphingolipid-like compound that enhances the accumulation of yeast sphingolipids and 2-hydroxy fatty acids. These lipids occur both as freely extractable and cell bound components in yeast fermentations. Both free and bound 2-hydroxy fatty acids produced byPichia sydowiorum NRRL Y-7130 were increased when fumonisin B₁ (50 mg/L) was added to the usual growth medium containing yeast extract/malt extract/peptone/glucose. Fumonisin-treated cultures contained 38 mg/L more 2-hydroxyhexadecanoic and 15 mg/L more 2-hydroxyoctadecanoic acids than did untreated cultures. By contrast, fumonisin inhibited the accumulation of free 8,9,13-trihydroxydocosanoic acid inRhodotorula sp. YB-2501 cultures, leading to 240 mg/L lower trihydroxy acid production than by untreated cultures.     

Production of β‐galactosidase from recombinant Saccharomyces cerevisiae grown on lactose

Improved productivity and costs reduction in fermentation processes may be attained by using flocculating cell cultures. The production of extracellular heterologous β‐galactosidase by recombinant flocculating Saccharomyces cerevisiae cells, expressing the lacA gene (coding for β‐galactosidase) of Aspergillus niger under the ADHI promotor and terminator in a bioreactor was studied. The effects of lactose concentration and yeast extract concentration on β‐galactosidase production in a semi‐synthetic medium were analysed. The extracellular β‐galactosidase activity increased linearly with increasing initial lactose concentrations (5–150 g dm^?3). β‐Galactosidase production also increased with increased yeast extract concentration. During the entire fermentation, no accumulation of the hydrolysed sugars, glucose and galactose, was observed. The catabolic repression of the recombinant strain when cultured in a medium containing equal amounts of glucose and galactose was confirmed. In complete anaerobiosis, the fermentation of lactose resulted in a very slow fermentation pattern with lower levels of β‐galactosidase activity. The bioreactor operation together with optimisation of culture conditions (lactose and yeast extract concentration) led to a 21‐fold increase in the extracellular β‐galactosidase activity produced when compared with preliminary Erlenmeyer fermentations. Copyright © 2004 Society of Chemical Industry     

Statistical optimization of anticholesterolemic drug lovastatin production by the red mold Monascus purpureus

Lovastatin (HMG-CoA reductase inhibitors), is an important anticholesterolemic drug which inhibits the conversion of HMG-CoA to mevalonate in the biosynthesis of cholesterol. Plackett–Burman statistical screening of 12 media components and subsequent optimization of significant parameters by response surface methodology for the biotechnological production of lovastatin by Monascus purpureus MTCC 369 was studied. In this study, the statistical analysis of Plackett–Burman experimental results showed that the medium components glucose, peptone, MnSO₄·H₂O, NaCl and NH₄Cl as the significant components influencing the lovastatin production. The most significant medium components, glucose, peptone and MnSO₄·H₂O which have confidence level of more than 95% were further optimized using a full factorial central composite design of the response surface methodology. Maximum lovastatin production of 97.5 mg l^?1 was obtained after 14 days of fermentation period in the optimized medium containing, glucose, 52.61 g l^?1 peptone, 16.65 g l^?1; NH₄Cl, 1 g l^?1; KH₂PO₄, 1 g l^?1; yeast extract, 3 g l^?1; K₂HPO₄, 1 g l^?1; KNO₃, 0.5 g l^?1; MgSO₄·7H₂O, 0.2 g l^?1; MnSO₄·H₂O, 0.418 g l^?1; NaCl, 0.5 g l^?1; CaCl₂·2H₂O, 0.1 g l^?1 and FeSO₄·7H₂O, 0.001 g l^?1 at 30 °C and 120 rpm. The production of lovastatin by M. purpureus MTCC 369 in the optimized medium was found to be four times higher than the basal medium in the submerged fermentation. The statistical experimental design serves as an efficient tool for screening large number of variables with minimum number of experiments and optimizing the significant variables for enhancing the production of lovastatin.     

Continuous alcohol production from whey permeate using immobilised cell reactor systems

The present paper reports the performance of a bioreactor packed with alginate-entrapped Kluyveromyces marxianus NCYC179 for continuous fermentation of whey permeate to ethanol. A maximum ethanol productivity as 28.21 gl^?1 h^?1 was attained at D=0.42h^?1 and 75% lactose consumption (substrate feed rate in the inflowing medium was 200 g lactose I^?1). However, the higher dilution rates (0.6-1.Oh^?1) resulted in poor productivities and higher substrate washout in the effluent samples. The maximum specific ethanol production (qpi) and maximum specific lactose uptake (qsi) of the immobilised Kluyveromyces marxianus NCYC179 was found to be 3.88g ethanol/g immobilised cell/hx10^?2 and 8.75g lactose consumed/g immobilised cell/hx10^?2 respectively. A bead size of 2.5 mm in diameter and activation period of 24h of alginate beads in lactose solution (10%) prior to their packing in column reactor were found to support the efficient working of the bioreactor. The immobilised cell bioreactor system was operated continuously at a constant dilution rate of 0.15h^?1 and 10% lactose for 562 h without any significant change in the efficiency (varied from 84 to 88% of theoretical) and viability of the entrapped yeast cells (dropped from 84 to 81%).