Optimization of fermentation conditions for production of xylanase by a newly isolated strain,Penicillium thiersii ZH-19

The objective of this study was to maximize production of xylanase by a newly isolated strain Penicillium thiersii ZH-19. Response surface methodology was employed to study the effects of significant factors such as pH, temperature, xylan concentration, and cultivation time, on the production of xylanase by Penicillium thiersii ZH-19. The optimal fermentation parameters for enhanced xylanase production were found to be pH 7.72, temperature 24.8°C, xylan 13.2 g l⁻¹ and the fermentation time 125.8 h. The model predicted a xylanase activity of 75.24 U ml⁻¹. Verification of the optimization showed that the maximum xylanase production reached 73.50 U mL⁻¹ in the flask experiments and 80.23 U mL⁻¹ in the scale of 15-L fermenter under the optimal condition.     

Optimization of the spore production of Penicillium roqueforti in solid substrate fermentation on buckwheat seeds

Summary The effect of substrate (buckwheat seeds) pretreatment on the growth and the sporulation behaviour of Penicillium roqueforti is presented. When a saccharifying enzyme (-amylase) is added to a medium which exhibits a low water content (0.46 g water/g initial dry matter, IDM), a more rapid internal colonization of the seeds occurs, but the final spore production does not increase and remains close to 8.10⁹ spores/g dry matter (DM) at 500 h. No carbon source limitation is then observed. The addition of casein hydrolysate to this medium gives rise to a great increase of the sporulation, since 14.5 10⁹ spores/g DM are obtained after 600 h. This result is attained by a better spore yield from the mycelium, the substrate colonization being unchanged. High water content (0.60 g water/g IDM) of buckwheat seeds induces a shorter cultivation time along with a higher biomass production. However, the spore content of the medium remains close to the low water content one, but 60% total spores are external against 30% to 35% in the other media.     

Screening and identification of a Penicillium brevicompactum strain isolated from the fruiting body of Inonotus obliquus and the fermentation production of mycophenolic acid

Mycophenolic acid (MPA) is a fungal metabolite with a variety of biological activities and widely applied in clinical practices. We herein aimed to isolate a new Penicillium brevicompactum strain from the fruiting body of Inonotus obliquus to improve the production of MPA. The fruiting body of Inonotus obliquus was used to isolate P. brevicompactum strains. Identification of the P. brevicompactum strain was performed by sequencing and phylogenetic tree analysis. HPLC assay was conducted to identify the production of MPA. Submerged liquid fermentation and bi-directional fermentation were applied to improve the yield of MPA. The candidates of the P. brevicompactum strain were isolated and screened from the fruiting body of Inonotus obliquus collected from Changbai mountains in China. Based on sequencing and phylogenetic tree analysis of 18S rDNA-ITS, the strain MC-4 was finally identified as P. brevicompactum. And HPLC assay indicated that the isolated P. brevicompactum strain could produce MPA in metabolic products. The optimized conditions of submerged liquid fermentation were as follows: 100 g/L Chinese yam in a liquid PDB medium, pH 6, fermentation temperature of 24 °C, shaker speed of 130 r/min, and fermentation time of 6 days. The maximum value of MPA production was 1.415 g/L after submerged liquid fermentation. Furthermore, the yield of MPA could be significantly increased to 1.537 g/L after bi-directional fermentation with the extractive from fructus Swietenia macrophylla (FSM). We demonstrated that a Penicillium brevicompactum strain isolated from the fruiting body of Inonotus obliquus can be used to improve the production of MPA by submerged liquid fermentation and bi-directional fermentation. This would provide a novel approach for more efficient and safer production of MPA.     

Spore production of Penicillium roqueforti by solid state fermentation: Stoichiometry, growth and sporulation behavior

The development of Penicillium roqueforti on buckwheat seeds proceeds roughly into four steps, involving a lag phase and three growth phases. First, it appears as a spore germination and external colonization of the grains by the mycelium. Then, mainly external sporulation and internal colonization of the seeds occur and finally internal sporulation takes place. The Stoichiometry of the growth and the sporulation is established. Kinetic experiments performed in a fixed bed reactor show that the growth of the microorganism (biomass production) may be estimated by the protein content of the medium. This growth occurs with a very low mu(max) value close to 0.030 h(-1). The chitin content of the medium is an indicator of the sporulation, just as the metabolic liquor (mainly water) produced during the course of a cultivation. The values of the observed respiratory quotient are close to those predicted by stoichiometry.     

Optimization of cultural conditions for tannase production by Pseudomonas aeruginosa IIIB 8914 under submerged fermentation

A tannase yielding bacterial strain was isolated from soil sample collected from the area situated nearby small-scale tannery. It was identified as Pseudomonas aeruginosa IIIB 8914. The bacterial strain produced extra-cellular tannase under sub-merged fermentation (Smf) using amla (Phyllanthus emblica), keekar (Acacia nilotica), jamoa (Eugenia cuspidate) and jamun (Syzygium cumini) leaves. Among different substrates, amla and keekar leaves resulted in maximal extra-cellular production of tannase. Various process parameters were studied to optimize the extra-cellular yield of tannase under Smf. Maximum yield of tannase i.e., 13.65 and 12.90 U/ml was obtained when Smf was carried out using amla and keekar leaves (2% w/v) respectively in minimal media supplemented with MgSO₄·7H₂O (amla)/HgCl₂ (keekar), NH₄NO₃ and 0.2% Tween 80; inoculated with 2% cell suspension, and incubated at 37°C for 24 h. The bacterial strain produced about 2 times (13.65 U/ml) higher yield of tannase than the highest reported yield of tannase (6 U/ml). Our finding suggests that agro residues in the form of amla and keekar leaves can be one of the best and cost effective alternatives to the costly pure tannic acid for industrial production of microbial tannase.     

5-酮基-D-葡萄糖酸发酵生产的工艺条件优化

葡萄糖酸氧化杆菌可将葡萄糖转化为5-酮基-D-葡萄糖酸(5-KGA),而5-KGA是重要食品添加剂L(+)-酒石酸的合成前体。为提高5-KGA产量及其对葡萄糖的转化率,对5-KGA发酵生产的工艺条件进行优化。在摇瓶水平最适的培养基和培养条件下,5-KGA最高产量为19.7 g/L,较优化前提高43.8%。在5 L发酵罐上控制恒定pH值5.5、溶氧浓度15%条件下,5-KGA产量达到46.0 g/L,较摇瓶最高产量提高1.3倍,应用葡萄糖流加工艺,5-KGA最高产量达到75.5 g/L,转化率超过70%,与已见报道的最高水平相比提高了32.0%,为实现微生物发酵生产5-KGA、进而合成L(+)-酒石酸的工业化提供了切实有效的途径。     

Cyclopiazonic acid production by submerged cultures of Penicillium and Aspergillus strains

Abstract 62 isolates of Penicillium and Aspergillus were screened for cyclopiazonic acid (CPA) production by surface and submerged culture on different media. The production of this mycotoxin was restricted to Penicillium camembertii group II (and its domesticated form P. camembertii ), P. griseofulvum , and Aspergillus flavus (and its domesticated form A. oryzae ). The best yield of CPA was obtained by a strain of P. griseofulvum , but several strains of P. camembertii group II were also good producers. Propionic acid (500 and 1000 mg/l medium) did not enhance the production of CPA. The best yields of CPA were obtained in submerged culture, but in some cases growth and CPA production only occured in surface culture. A simplified procedure for isolation of CPA is described.     

Optimization of mycophenolic acid production in solid state fermentation using response surface methodology

Mycophenolic acid (MPA) can be produced in solid state fermentation. An isolate of Penicillium brevi-compactum ATCC 16024 grown on moist wheat bran produced a titre of 425 mg per kg of wheat bran. Central composite rotatable design and response surface methodology were employed to derive a statistical model for media optimization towards production of mycophenolic acid. Five levels with a five factorial design were adopted. The correlation coefficient was 0.82, ensuring a satisfactory adjustment of the model to the experimental values. This statistical design was very effective in improving the titre of mycophenolic acid up to 3286 mg per kg of wheat bran. Received 24 July 1998/ Accepted in revised form 4 December 1998     

Optimization of submerged fermentation medium for citrinin-free monascin production by Monascus

Microbial fermentation of citrinin-free Monascus pigments is in favor in the development of food industry. This study investigated the influences of carbon source, nitrogen source, and mineral salts on the cell growth, monascin (MS), and citrinin (CT) production in Monascus M9. A culture medium composition was established for maximizing the production of citrinin-free MS in submerged culture, as follows: 50?g/L Japonica rice powder, 20?g/L NH₄NO₃, 3?g/L NaNO₃, 1.5?g/L KH₂PO₄, 1?g/L MgSO₄?·?7H₂O, 0.2?g/L MnSO₄. Under these conditions, no CT was detectable by high performance liquid chromatography. The yield of MS reached 14.11?mg/g, improving approximately 30% compared with before optimization.     

Optimizing the fermentation conditions and enhanced production of keratinase from Bacillus cereus isolated from halophilic environment

Keratinase degrading Bacillus cereus was isolated from the halophilic environment in Tamilnadu, India and keratinase production was optimized using wheat bran substrate. Of the screened bacterial isolates, four were found to have the ability to produce keratinolytic enzyme. The process parameters were optimized using one-variable-at-a-time approach and response surface methodology. Supplementation of 1% lactose supported more keratinase production (120?U/g). Among the selected nitrogen sources, addition of casein significantly enhanced maximum keratinase production (132.5?U/g). Among the ions, manganese chloride significantly enhanced keratinsase production (102.6?U/g), however addition of zinc sulphate and copper sulphate decreased keratinase production. The maximum keratinase production was obtained in the wheat bran medium containing 1% lactose, 0.5% manganese with 80% moisture (292?U/g). Statistics based contour plots were generated to explore the variations in the response surface and to find the relationship between the keratinase yield and the bioprocess conditions.     

Optimization of fermentation conditions for the production of ethylene-diamine-disuccinic acid by Amycolatopsis orientalis

The production of EDDS (ethylene-diamine-disuccinic acid), a potential substitute for EDTA, has been optimized up to a product concentration of 20 grams per litre in fermentations of Amycolatopsis orientalis. Decisive steps for the increase in productivity were variation of the synthetic medium composition, investigation of the influence of metal ions on product formation, controlled feeding of carbon and nitrogen sources in fed-batch fermentations and improvement of the downstream processing steps. Received 05 May 1997/ Accepted in revised form 13 August 1997     

出芽短梗霉产聚苹果酸发酵条件的优化

【背景】出芽短梗霉可发酵葡萄糖生成聚苹果酸,但存在转化率和转化效率低等瓶颈,阻碍其实现商业化生产。【目的】通过优化发酵培养条件,提高出芽短梗霉的聚苹果酸产量、糖酸转化率和生产强度。【方法】采用单因素试验优化适宜出芽短梗霉BK-10菌株产生聚苹果酸的培养条件,通过Plackett-Burman法对培养基组分筛选显著性影响因素,并对其培养基中无机盐进行正交试验优化,最后进行5 L发酵罐验证。【结果】最优培养基配方和培养条件:100 g/L葡萄糖,1.5 g/L尿素,0.20 g/L KH_2PO_4,0.20 g/L ZnSO_4,0.05 g/L MgSO_4,0.75 g/L KCl,30 g/L CaCO_3,0.01%吐温-80,发酵温度26°C,250 mL摇瓶装液量50 mL。【结论】通过优化,聚苹果酸的糖酸转化率达到0.71 g/g,生产强度达到0.89 g/(L·h),较优化前分别提高了18.33%和71.15%,为发酵葡萄糖合成聚苹果酸进而生产L-苹果酸工艺的工业化生产奠定经济性基础。     

Optimization of fermentation conditions for ethanol production from whey

Summary Optimal conditions for ethanol production in 7% whey solutions by the yeast Candida pseudotropicalis ATCC 8619 included initial pH of 4.57 and 30°C. Complete fermentation of the available lactose took place without supplementary nutrients; additions of nitrogen or phosphorus salts, yeast extract or corn steep liquor resulted in increased yeast production and lower ethanol yields. A positive correlation was observed between increases in yeast inocula and lactose utilization and ethanol production rates; 8.35 g/l of ethanol was obtained within 22 h by using yeast inoculum of 13.9 g/l. No differences in fermentation rates or ethanol yields were observed when whole or deproteinized whey solutions were used. Concentrated whey permeates, obtained after removal of the valuable proteins from whey, can be effectively fermented for ethanol production.     

Optimization of culture conditions and bench-scale production of anticancer enzyme L-asparaginase by submerged fermentation from Aspergillus terreus CCT 7693

L-Asparaginase amidohydrolase (EC 3.5.1.1) has received significant attention owing to its clinical use in acute lymphoblastic leukemia treatment and non-clinical applications in the food industry to reduce acrylamide (toxic compound) formation during the frying of starchy foods. In this study, a sequential optimization strategy was used to determine the best culture conditions for L-asparaginase production from filamentous fungus Aspergillus terreus CCT 7693 by submerged fermentation. The cultural conditions were studied using a 3-level, central composite design of response surface methodology, and biomass and enzyme production were optimized separately. The highest amount of biomass (22.0?g·L^?1) was obtained with modified Czapek–Dox medium containing glucose (14?g·L^?1), L-proline (10?g·L^?1), and ammonium nitrate (2?g·L^?1) fermented at 37.2?°C and pH 8.56; for maximum enzyme production (13.50?U·g^?1), the best condition was modified Czapek–Dox medium containing glucose (2?g·L^?1), L-proline (10?g·L^?1), and inoculum concentration of 4.8?×?10⁸ espore·mL^?1 adjusted to pH 9.49 at 34.6?°C. The L-asparaginase production profile was studied in a 7?L bench-scale bioreactor and a final specific activity of 13.81?U·g^?1 was achieved, which represents an increase of 200% in relation to the initial non-optimized conditions.     

A novel process for the production of penitrem mycotoxins by submerged fermentation of Penicillium nigricans

A strain of Penicillium nigricans, which produces both the antifungal antibiotic griseofulvin and tremorgenic penitrem mycotoxins concurrently in static liquid culture, also elaborated both metabolites in submerged culture when stimulated by calcium chloride to sporulate. Maximum yield of penitrems (60 mg l-1) occurred within 5 d in a 60 l stirred fermenter, thus constituting the first significant process for penitrem production in submerged culture.     

Optimization of culture conditions and bench-scale production of L-asparaginase by submerged fermentation of Aspergillus terreus MTCC 1782

Optimization of culture conditions for L-asparaginase production by submerged fermentation of Aspergillus terreus MTCC 1782 was studied using a 3-level central composite design of response surface methodology and artificial neural network linked genetic algorithm. The artificial neural network linked genetic algorithm was found to be more efficient than response surface methodology. The experimental L-asparaginase activity of 43.29 IU/ml was obtained at the optimum culture conditions of temperature 35 degrees C, initial pH 6.3, inoculum size 1% (v/v), agitation rate 140 rpm, and incubation time 58.5 h of the artificial neural network linked genetic algorithm, which was close to the predicted activity of 44.38 IU/ml. Characteristics of L-asparaginase production by A. terreus MTCC 1782 were studied in a 3 L bench-scale bioreactor.     

Optimization of fermentation conditions for alcohol production

The quantitative effects of carbohydrate levels, degree of initial saccharification, glucoamylase dosage, temperature, and fermentation time were investigated using a Box-Wilson central composite design protocol. With Saccharomyces cerevisiae ATCC 4126, it was found that the use of a partially saccharified starch substrate markedly increased yields and attainable alcohol levels. Balancing the degree of initial saccharification with the level of glucoamylase used to complete hydrolysis was found necessary to obtain optimum yields. The temperature optimum was found to be 36 degrees C. The regression equations obtained were used to model the fermentation in order to determine optimum fermentation conditions.     

乳牛肝菌液态发酵生长条件的优化

采用响应曲面法对乳牛肝菌发酵培养基及发酵条件进行优化,以麦芽糖、蛋白胨和装液量3个因素为变量,分析乳牛肝菌液态发酵产菌丝体的最佳条件。实验结果表明,乳牛肝菌发酵的关键因子值分别为麦芽糖33．03g/L,蛋白胨6．95g/L,装液量为102．21mL／250mL时,可得到最大菌丝体生物量23．44g/L（干重）。     

星形孢菌素的发酵条件优化

提高抗生素在产生菌中的表达效价,从而降低生产成本,是实现抗生素生产应用的重要基础.星形孢菌素是一种非特异性的蛋白激酶抑制剂,能够诱导多种类型的细胞凋亡,但目前星形孢菌素生产菌株的表达效价均较低,达不到生产要求,使其应用受到限制[1-4].     

Culture conditions for enhanced cellulase production by a native strain of Penicillium purpurogenum

A cellulolytic wild-type strain of Penicillium purpurogenum was isolated from a soil sample in southern Chile. It grew best at 28°C from an inoculum of 4×10⁷ spores/100 ml medium. Highest endoglucanase activity was with Sigmacell as carbon source and corn steep liquor as nitrogen source. Wheat bran enhanced the production of endoglucanase and -glucosidase. The enzymes in the crude supernatants were stable up to 50°C and between pH 4.4 and 5.6 for 48 h.J.Steiner and C. Socha are with the Facultad de Ciencias Quimicas y Farmacéuticas, Universidad de Chile, Casilla 233, Santiago 1, Chile; J. Eyzaguirre is with the Laboratorio de Bioquímica, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile.