Optimization of lipase production by Penicillium simplicissimum in soybean meal

BACKGROUND: Lipase production by Penicillium simplicissimum using soybean meal as substrate has been investigated. A factorial design technique was used to evaluate the effects of incubation temperature, initial moisture of the meal and substrate supplementation with low cost supplements, on lipase production. Soybean oil and wastewater from a slaughterhouse, which is rich on oil and fat, corn steep liquor and yeast hydrolysate, were tested as supplementary carbon and nitrogen sources. RESULTS Cultivation conditions were optimized for the production of lipase by factorial design and response surface methodology. Results show that the microorganism produces very low protease activity (0.21 U gds^?1 dry substrate), which helps to maximize lipase production. Soybean meal without supplements appears to be the best medium of those tested for lipase production by P. simplicissimum. CONCLUSION: This work showed that temperature and moisture are the factors that most strongly influence lipase production by P. simplicissimum using soybean meal as substrate. The growth conditions that optimize lipase production are 27.5 °C using substrate with 550 g kg^?1 of initial moisture. In optimum conditions lipase activity of 30 U gds^?1 dry substrate was obtained. Copyright © 2007 Society of Chemical Industry     

Media Optimization for Poly(β-hydroxybutyrate) Production Using Azotobacter Beijerinckii

In the present study, efforts were made to optimize the growth of Azotobacter beijerinckii in the media with essential nutrients for production of PHB. The effects of temperature, agitation rate, carbon and nitrogen source concentrations on microbial grows and PHB production were investigated. Glucose and ammonium chloride were used as carbon and nitrogen source, respectively. The optimal temperature for the growth and PHB synthesis appeared to be 30°C. However, over the range of 25–38°C, the effect of temperature was not very significant. Fermentation under controlled conditions such as agitation rate of 250 rpm, incubated inoculums for 15 h, fermentation temperature at 30°C, and fermentation time of 72 h was performed. Glucose concentration of 30 to 60 g/l with increment of 10 g/l and ammonium chloride in the range of 0.5 to 2 g/l with increment of 0.5 g/l were utilized as carbon and nitrogen sources, respectively. The PHB production was maximized at the desired concentration of glucose (50 g/l) and ammonium chloride (1.5) for carbon and nitrogen sources, respectively. A. beijerinckii exhibited maximum biomass of 17.31 g/l with a PHB concentration of 5.84 g/l. Under the best conditions, PHB constituted up to 34% of dry cell mass after 64 h of culture. The average biomass yield coefficient on glucose was about 0.57 kg/kg.     

Medium Optimization for Enhanced Production of Protease with Industrially Desirable Attributes from Bacillus subtilis K-1

Microbial proteases due to their huge application potential have attracted considerable research attention and account for more than 60% of the worldwide enzyme sales. However, large-scale industrial application of proteases is hindered due to their poor performance under relatively hostile industrial conditions (extremes of temperature, pH) and the high production cost. In the current study, the production of a thermostable and wide-range pH stable protease was accomplished from a newly isolated Bacillus subtilis K-1 strain using cost-effective agricultural residues. Process optimization for protease production was conducted by employing one-variable-at-a-time and statistical approaches. The most significant variables for protease production were identified as incubation time, soybean meal, mustard cake, and wheat bran. Optimization of these variables by central composite design of response surface methodology resulted in a substantial protease yield enhancement (112%). Exploitation of agricultural wastes as substrates may pave the way for cost-effective production of protease with industrially desirable attributes.     

Optimization of cultivation conditions for fungichromin production from Streptomyces padanus PMS-702

A novel strain, Streptomyces padanus PMS-702, was employed to produce fungichromin (FC, a polyene macrolide antibiotic) in a shake flask cultivation. In comparing the effects of various carbon and nitrogen sources on PMS-702 cultivation, it was found that glucose and soybean meal medium yielded the highest FC within 2 days. Factors such as medium composition, cultivation temperatures, and initial pH were optimized for FC production with response surface methodology (RSM). The optimal cultural condition obtained is as follows: glucose 11.2 g/L, soybean meal 11.2 g/L, CaCO₃ 0.46 g/L, temperature 31.7 °C, and an initial pH 5.5. Under these conditions, FC production reached 112 mg/L, about an increase of 2.86 times, as compared to results under basic conditions.     

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.     

The fermentative production of magnamycin by Streptomyces halstedii

Production of magnamycin in different fermentation media by Streptomyces halstedii was studied to select the most suitable for the formation of the antibiotic. Two distinct phases were observed during the fermentative production of magnamycin. The first phase was characterised by vegetative growth, while the second phase was distinguished by formation of the antibiotic. The optimum initial pH value of the medium was 6.12. Glucose was used as carbon source. The best concentrations of glucose and starch supporting biosynthesis of magnamycin were 8.0 and 15.0 g/litre respectively. Soyabean meal was the most suitable organic nitrogen source. The most suitable concentrations of soyabean meal, yeast extract and corn steep liquor were 8.0, 2.0 and 16.0 g/litre respectively.     

豆粕水解液为氮源细菌厌氧流加发酵生产L-乳酸

采用细菌厌氧发酵法生产L-乳酸,由实验确定了最佳接种量、发酵温度和pH调节剂,考察了初始葡萄糖浓度对L-乳酸生产的影响,确定初始糖浓度为70~90 g/L时得率、产率、最终生物量分别达到92.68 g/g, 3.17 g/(L×h)和8.5′107 mL-1. 为进一步降低L-乳酸生产成本,以豆粕水解液为氮源代替酵母粉,同时应用流加发酵技术,L-乳酸产量、得率、产率及转化率分别达到155 g/L, 95.5 g/g, 1.64 g/(L×h)和96.9%. 在保证L-乳酸最终浓度的同时可降低生产成本,为进一步工业化奠定了基础.     

Mn‐peroxidase production by Panus tigrinus CBS 577.79: response surface optimisation and bioreactor comparison

This study reports the statistical optimisation through response surface methodology of the growth medium for Panus tigrinus manganese‐dependent peroxidase (MnP) production in shaken culture. Three crucial variables, including carbon source, malonic acid and Mn²⁺, were optimised in a nitrogen‐limited medium. Sucrose was the best carbon source for MnP production. Mn²⁺ ions and malonic acid significantly stimulated MnP production at an optimal concentration of 53 mg dm^?3 and 8.2 mmol dm^?3, respectively, resulting in 0.83 U cm^?3. Further experiments were performed in lab‐scale stirred tank (STR) and bubble‐column (BCR) reactors using the previously optimised liquid medium. BCR proved to be more adequate than STR in supporting MnP production, leading to 3700 U dm^?3 after 144 h with a productivity of 25.7 U dm^?3 h^?1. On a comparative basis with other production data in lab‐scale reactors, these results appear to be compatible with scale transfer. Copyright © 2006 Society of Chemical Industry     

Optimization of alkaline protease production from Shewanella oneidensis MR‐1 by response surface methodology

BACKGROUND: The proteases are among the most important groups of enzymes. Therefore, it is important to produce inexpensive and optimized media for large‐scale commercial production. In the present work, three different Shewanella species were screened on skim milk agar medium for their ability to produce alkaline protease. The effects of different culture conditions were optimized for alkaline protease production by S. oneidensis MR‐1 using a Box–Behnken design combined with response surface methodology (RSM). RESULTS: Highest yield (112.90 U mL^?1) of protease production was obtained at pH 9.0, a temperature of 30 °C, glucose (12.5 g L^?1), tryptone (12.5 g L^?1) and an incubation period of 36 h. A second‐order polynomial regression model was used for analysis of the experiment. The experimental values were in good agreement with predicted values, with correlation coefficient 0.9996. CONCLUSION: Carbon and nitrogen, pH, temperature and incubation period were chosen as the main factors to be used in an experimental design for optimization to produce low‐cost enzymes, potentially for use on an industrial scale. A 60% increase in enzyme activity was achieved in the optimized medium compared with the original medium. Copyright © 2008 Society of Chemical Industry     

抗生素AGPM摇瓶发酵条件的正交实验

采用正交实验设计考察了培养基组成对新型抗生素AGPM发酵的影响,改进后在培养基组成为(g/L)：葡萄糖5, 玉米淀粉40, 黄豆饼粉16, 玉米浆2 ml, K2HPO4 1.0, MgSO4×7H2O 0.5, NaCl 0.5, 淀粉酶0.05及pH 5.5的条件下,单位发酵液的活性提高了18.9倍;同时表明较高的碳氮比对抗生素AGPM的合成有利.     

Use of sweet sorghum juice for lactic acid fermentation: preliminary steps in a process optimization

BACKGROUND: Lactic acid has many applications in the chemical industries and it can be produced economically by microorganisms using biomass raw materials of different origins. Sweet sorghum juice is a high sugar content raw material with potential for lactic acid production because after hydrolysis of its sucrose content the remaining glucose and fructose can supply the carbon demand of most lactic acid bacteria. However, satisfying the nitrogen and B‐vitamin needs of the bacteria by supplementation with yeast extract and/or other alternative nitrogen‐containing supplements can make the process too expensive. RESULTS: Using a statistical optimization process much of the yeast extract can be replaced by a cheaper alternative nitrogen source, namely wheat gluten. This resulted in a fermentation with 99% lactic acid yield and 3.04 g L^?1 h^?1 volumetric productivity. CONCLUSION: Using response surface methodology (RSM) media optimization was performed for lactic acid fermentation with an industrially acceptable result, reducing the costs of raw materials by half, replacing yeast extract by an alternative nitrogen source and applying yeast extract only as a source of micro‐elements (vitamins, salts, etc.) Copyright © 2010 Society of Chemical Industry     

Biogenic PHA nanoparticle synthesis and characterization from Bacillus subtilis NCDC0671 using orange peel medium

The present research work was initiated to synthesize biogenic polyhydroxyalkanoate (PHA) nanoparticles from Bacillus subtilis NCDC0671 using orange peel medium. Sequential and systematic optimization of bioprocess variables was performed using “one-factor-at-a-time” approach for maximizing PHA yield. Maximum PHA yield was achieved under optimized conditions of temperature (37°C), pH (7), carbon source (sucrose), and nitrogen source (beef extract) on 72?h of fermentation using B. subtilis NCDC0671. PHA nanoparticles were synthesized using triple emulsion method and conjugated with drug levofloxacin. Dialysis method was used to evaluate the in vitro drug releasing efficacy of PHA–levofloxacin nanoparticles.     

Optimization and Characterization of Biosurfactant Rhamnolipid Production by Pseudomonas aeruginosa Isolated from an Artificially Contaminated Soil

Biosurfactants are surfactants biologically produced by microorganisms, presenting several advantages when compared to synthetic surfactants. Pseudomonas aeruginosa is known for producing rhamnolipids, considered one of the most interesting types of biosurfactants due to their high yields, when compared to other types. In this work, the production of rhamnolipid from P. aeruginosa was optimized. At first, the Plackett–Burman design was used to select most significant variables affecting the biosurfactant production yield among nine variables—carbon–nitrogen ratio, carbon concentration, nitrogen source, pH, cultivation time, potassium and magnesium concentrations, agitation, and temperature. Then, using main variables, a central point experimental design aiming to optimize rhamnolipid production was performed. The maximum biosurfactant concentration obtained was 0.877 mg L⁻¹. The rhamnolipid also displayed a great emulsification rate, reaching approximately 67%, and the ability to reduce water surface tension from 72.02 to 35.26 mN m⁻¹ at a critical micelle concentration (CMC) of 127 mg L⁻¹, in addition to presenting a good stability when exposed to wide pH and salinity ranges. The results suggest that rhamnolipids are promising substitutes for synthetic surfactants, especially due to lower impacts on the environment.     

Lipase‐mediated methanolysis of soybean oils for biodiesel production

BACKGROUND: Biodiesel is increasingly perceived as an important component of solutions to the important current issues of fossil fuel shortages and environmental pollution. Biocatalysis of soybean oils using soluble lipase offers an alternative approach to lipase‐catalyzed biodiesel production using immobilized enzyme or whole‐cell catalysis. The central composite design (CCD) of response surface methodology (RSM) was used here to evaluate the effects of enzyme concentration, temperature, molar ratio of methanol to oil and stirring rate on the yield of fatty methyl ester. RESULTS: Lipase NS81006 from a genetically modified Aspergillus oryzae was utilized as the catalyst for the transesterification of soybean oil for biodiesel production. The experimental data showed that enzyme concentration, molar ratio of methanol to oil and stirring rate had the most significant impact on the yield of fatty methyl ester; a quadratic polynomial equation was obtained for methyl ester yield by multiple regression analysis. The predicted biodiesel yield was 0.928 (w/w) under the optimal conditions and the subsequent verification experiments with biodiesel yield of 0.936 ± 0.014 (w/w) confirmed the validity of the predicted model. CONCLUSION: RSM and CCD were suitable techniques to optimize the transesterification of soybean oil for biodiesel production by soluble lipase NS81006. The related lipase NS81006 reuse stability, chemical or genetic modification, and transesterification mechanism should be taken into consideration. Copyright © 2007 Society of Chemical Industry     

Succinic Acid Production in Fed‐Batch Fermentation of Anaerobiospirillum succiniciproducens Using Glycerol as Carbon Source

Considering glycerol as an inexpensive alternative carbon source, the optimal glycerol concentration for succinic acid production with Anaerobiospirillum succiniciproducens was identified in shake‐flask trials. The addition of a defined amount of glucose improved the growth and succinic acid productivity significantly. In fed‐batch processes with glycerol as sole substrate, a maximum succinic acid concentration and product substrate yield were obtained. The addition of glucose led to a 2.5‐fold increased succinic acid concentration whereas the product substrate yield remained nearly constant.     

γ‐Linolenic acid production by Arthrospira platensis using different carbon sources

Arthrospira platensis (Spirulina) is an important source of pharmaceuticals and nutraceuticals such as γ‐linolenic acid (GLnA). Effects of several parameters including carbon source (glucose, ethanol, and acetic acid), type of addition (batch or fed‐batch), light intensity (2.0, 3.5, and 5.0 klx) were investigated in the mixotrophic cultivation of Spirulina (using both light and carbon source). The obtained Spirulina was analyzed in terms of biomass, lipid, and GLnA production. Compared to photoautotrophic conditions (i.e., when using light without external carbon source), the biomass concentration was found to be higher when Spirulina was grown mixotrophically. Similarly, the lipid content as well as the GLnA was found at higher levels when using mixotrophic conditions. Effects of different light intensities under photoautotrophic and mixotrophic conditions were studied. The highest final biomass concentration (2.17 g/L), lipid yield of culture medium (128 mg/L), and GLnA yield of the culture medium (32 mg/L) were obtained at the highest light intensity of 5.0 klx. It was also demonstrated that the biomass, lipid, and GLnA production under different light intensities, using ethanol and acetic acid, could be comparable and even better than those of glucose. Practical applications: Spirulina is an attractive source of functional components such as γ‐linolenic acid (GLnA). Results of this study suggest that carbon sources such as ethanol and acetic acid can also be used for the production of GLnA by Spirulina under mixotrophic cultivation (using light and external carbon source).     

Fermentative production of L(+)‐lactic acid from starch hydrolyzate and corn steep liquor as inexpensive nutrients by batch culture of Enterococcus faecalis RKY1

BACKGROUND: Attempts were made to determine the lactic acid production efficiency of novel isolate, Enterococcus faecalis RKY1 using four different starches (corn, tapioca, potato, and wheat starch) with different concentrations (50, 75, 100, and 125 g L^?1) and corn steep liquor as an inexpensive nitrogen source. RESULTS: The yield of lactic acid from each starch was higher than 95% based on initial starch concentrations. High lactic acid concentration (129.9 g L^?1) and yield (1.04 g‐lactic acid g^?1‐starch) were achieved faster (84 h) from 125 g L^?1 of corn starch. Among the starches used, tapioca starch fermentation usually completed in a shorter incubation period. The final dry cell weight was highest (7.0 g L^?1) for the medium containing 75 g L^?1 of corn starch, which resulted in maximum volumetric productivity of lactic acid (3.6 g L^?1 h^?1). The addition of 30 g L^?1 corn steep liquor supplemented with a minimal amount of yeast extract supported both cell growth and lactic acid fermentation. CONCLUSION: Enterococcus faecalis RKY1 was found to be capable of growing well on inexpensive nutrients and producing maximum lactic acid from starches and corn steep liquor as lower‐cost raw materials than conventionally‐used refined sugars such as glucose, and yeast extract as an organic nitrogen source in laboratory‐scale studies. These fermentation characteristics are prerequisites for the industrial scale production of lactic acid. Copyright © 2008 Society of Chemical Industry     

Effect of Natural and Pretreated Soybean Hulls on Enzyme Production by Trichoderma reesei

The enzyme induction utility of soybean hulls (SBH), consisting in excess of 50 wt% non-starch polysaccharides (NSP) cellulose, hemicellulose, and pectin, was studied through cultivation of the carbohydrase-producing fungus Trichoderma reesei Rut C-30. Shake flask systems of T. reesei were grown in a medium consisting of defatted soybean flour as a nitrogen source and SBH, some of which were untreated and others pretreated by liquid hot water, alkaline, and supercritical carbon dioxide, as carbon source. Cellulase, xylanase, and polygalacturonase activities were measured for the systems, and the natural hull systems were found to yield optimum enzyme production. Controlled batch fermentation experiments were carried out to compare enzyme production resulting from media with Avicel^® (FMC BioPolymer, Philadelphia, PA, USA) versus natural SBH with and without soybean flour as the nitrogen source. Soybean hull fermentations were also performed at several pH levels to observe the effects on enzyme production. Soybean hulls induced comparable levels of cellulase, and higher levels of xylanase and polygalacturonase, than Avicel^®. With SBH, cellulase and xylanase production were enhanced at higher pH levels (6.0), and polygalacturonase was enhanced at lower pH levels (4.0–4.5). Enzyme production was largely unaffected by the presence of soybean flour as the nitrogen source.     

Lipase‐catalyzed production of medium‐chain triacylglycerols from palm kernel oil distillate: Optimization using response surface methodology

Optimization of lipase‐catalyzed esterification for the production of medium‐chain triacylglycerols (MCT) from palm kernel oil distillate and glycerol was carried out in order to determine the factors that have significant effects on the reaction system and MCT yield. Novozyme 435 from Candida antarctica lipase was found to have the highest activity at 52.87 ± 0.03 U/g. This lipase also produced the highest MCT yield, which is 56.67%. The effect of different variables on MCT synthesis was studied with a two‐level five‐factor fractional factorial design. The various variables include (1) reaction temperature, (2) enzyme load, (3) molecular sieves concentration, (4) reaction time and (5) molar substrate ratio. Reaction temperature, reaction time and molar substrate ratio strongly affect MCT synthesis (p <0.05). However, enzyme load and molecular sieve concentration did not have a significant (p >0.05) influence on MCT yield. Therefore, the significant variables such as reaction temperature, reaction time and molar substrate ratio were further optimized through central composite rotatable design (CCRD). Comparisons between predicted and experimental values from the CCRD optimization procedures revealed good correlation, implying that the quadric response model satisfactorily expressed the percentage yield of MCT in the lipase‐catalyzed esterification. The optimum MCT yield is 73.3% by using 2 wt‐% enzyme dosage, a molecular sieves concentration of 1 wt‐%, a reaction temperature of 90 °C, a reaction time of 10 h and a molar substrate ratio of 4 : 1 (medium‐chain fatty acid/glycerol). Experiments to confirm the predicted results using the optimal parameters were conducted and an MCT yield of 70.21 ± 0.18% (n = 3) was obtained.     

海洋微生物溶菌酶的发酵优化与中试生产

以海洋细菌S-12-86为试验菌株,采用摇瓶发酵优化的方式,研究培养基组分(碳源、氮源、碳源与氮源的比例、金属离子)与发酵条件(培养温度、接种体积分数、装液体积分数、起始pH值、产酶周期)对海洋微生物溶菌酶产量的影响,并进行中试放大试验。结果表明:该菌产酶最佳培养基组分为:葡萄糖10 g/L,蛋白胨5 g/L,MgSO45 g/L,CaCl22 g/L;最适发酵培养温度为30℃,接种体积分数为4.0%,装液体积分数为10.0%,起始pH值为8.0,发酵周期24 h。海洋细菌S-12-86发酵优化后的产酶量(25636.8 U/mL)较优化前的产酶量(14454.4 U/mL)提高了75.4%。海洋微生物溶菌酶中试发酵的产酶量达26697.87 U/mL。说明摇瓶发酵优化条件可以应用于海洋微生物溶菌酶中试生产上。