Production of organic acids from fermentation of mannitol, fructooligosaccharide and inulin by a cholesterol removing Lactobacillus acidophilus strain

AIMS: Assessment of individual production of organic acids by Lactobacillus acidophilus ATCC 4962 in the presence of mannitol, fructooligosaccharide (FOS) and inulin. METHODS AND RESULTS: The production patterns of individual organic acids by L. acidophilus ATCC 4962 were assessed using the experimental region for optimum cholesterol removal from the interaction between L. acidophilus ATCC 4962 and prebiotics selected in our previous study. The production of acetic and formic acids was growth associated and was greatly influenced by the inoculum size of the organism and the concentration of mannitol. The growth of the organism was repressed with the fermentation end products of FOS and inulin, which subsequently exhibited repressed production of acetic and formic acids as well. The inoculum size, mannitol and FOS linearly affected the formation of butyric acid and the response surface generated showed a correlation between butyric acid and acetic acid. The experimental regions with increased production of lactic acid showed cessation of growth of the organism, indicating inhibition of growth at high concentration of lactic acid. CONCLUSIONS: The production of individual organic acids was dependent on growth and the fermentability of prebiotics. Mannitol, FOS and inulin favoured the production of formic, lactic and butyric acids respectively. SIGNIFICANCE AND IMPACT OF THE STUDY: The fermentability of prebiotics to produce metabolites has been a controversial issue. Information gathered in this study provides a better understanding on the production of organic acids from fermentation of mannitol, FOS and inulin by L. acidophilus ATCC 4962, and on changes in their production as a response from interaction of factors.     

Optimization of anticancer exopolysaccharide production from probiotic Lactobacillus acidophilus by response surface methodology

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths in the Western world. Recently, much attention has been focused on decreasing the risk of CRC by consuming probiotics. In the present study, exopolysaccharide (EPS) extracted from Lactobacillus acidophilus was found to inhibit the growth of CaCo2 colon cancer cell line in a dose-dependent manner. The experiment was performed in both normoxic and hypoxic conditions, and EPS was found to reduce the survival of CaCo2 cell line in both the conditions. Quantitative polymerase chain reaction (qPCR) studies demonstrated that EPS treatment upregulated the expression of peroxisome proliferator activator receptor-γ (PPAR-γ) in both normoxia and hypoxia conditions, whereas it upregulated the expression of erythropoietin (EPO) in the normoxic condition, but there was no significant expression under hypoxic conditions. Hence, the EPS production was optimized by Plackett–Burman design followed by central composite rotatory design. The optimized production of EPS at 24 hr was found to be 400 mg/L. During batch cultivation the production peaked at 21 hr, resulting in an EPS concentration of 597 mg/L.     

Optimization of cholesterol removal by probiotics in the presence of prebiotics by using a response surface method

Lactobacillus casei ASCC 292 was grown in the presence of six prebiotics, namely, sorbitol, mannitol, maltodextrin, high-amylose maize, fructooligosaccharide (FOS), and inulin, in order to determine the combination of probiotic and prebiotics that would remove the highest level of cholesterol. A first-order model showed that the combination of L. casei ASCC 292, FOS, and maltodextrin was the most efficient for the removal of cholesterol, and the optimum experimental region was developed by using the steepest ascent. This led to the middle points of probiotic (1.70% [wt/vol]), FOS (4.80% [wt/vol]), and maltodextrin (6.80% [wt/vol]) for the development of a central composite design for optimization. Perturbation plot, response surface, and coefficient estimates showed that all three factors had significant quadratic effects on cholesterol removal, with FOS showing the most conspicuous quadratic change. A second-order polynomial regression model estimated that the optimum condition of the factors for cholesterol removal by L. casei ASCC 292 is 1.71% (wt/vol) probiotic, 4.95% (wt/vol) FOS, and 6.62% (wt/vol) maltodextrin. Validation experiments showed that the predicted optimum conditions were more efficient than the high and low levels of the factors and the center points. A response surface method proved reliable for developing the model, optimizing factors, and analyzing interaction effects. Analyses of growth, substrate utilization, growth yield, mean doubling time, and short-chain fatty acid (SCFA) production by the use of quadratic models indicated that cholesterol removal was growth associated. The concentration of L. casei ASCC 292 had the most significant quadratic effect on all responses studied, except for substrate utilization and SCFA production, which were significantly (P < 0.05) influenced by the interactions between the probiotic and both prebiotics, indicating that they were closely associated with the uptake of prebiotics.     

响应面法优化福鸽霉素发酵培养基

采用Plackett-Burman设计法,对影响纤维堆囊菌So ceMWXAB-125产生福鸽霉素的9个因素进行了筛选。结果表明,影响该菌产生福鸽霉素的主要营养因素为马铃薯淀粉、CaCl2和脱脂奶粉。在此基础上,采用响应面法对其中3个显著因子的最佳水平范围进行研究,利用Design-Expert软件进行二次回归分析得知,马铃薯淀粉、CaCl2和脱脂奶粉的质量浓度分别为8.05、2.72和10.00 g/L时,福鸽霉素的产量从67 mg/L提高到119.98 mg/L。     

Optimization of fermentation parameters in phage production using response surface methodology

Previously, we used computer-controlled fermentation technology to improve the yield of filamentous phage produced in Escherichia coli by 10-fold (Grieco et?al., Bioprocess Biosyst Eng 32:773-779, 2009). In the current study, three major fermentation parameters (temperature, dissolved oxygen [DO], and pH) were investigated using design of experiments (DOE) methodology. Response surface methodology (RSM) was employed to create a process model and determine the optimal conditions for maximal phage production. The experimental data fitted best to a quadratic model (p?相似文献   

嗜酸乳酸杆菌ATCC 4356菌株异源二聚体b-半乳糖苷酶的克隆表达

嗜酸乳酸杆菌(Lactobacillus acidophilus)的异源二聚体β-半乳糖苷酶属于糖苷水解酶2家族,由两个部分重叠、协同翻译的基因编码(lacL和lacM).[目的]克隆表达该酶并测定其酶学特性.[方法]参照已全基因组测序的嗜酸乳酸杆菌NCFM菌株,以嗜酸乳酸杆菌ATCC4356菌株基因组为模板,将lacL的RBS到lacM的终止子之间的序列(2834 bp)克隆到pQE31质粒上,并电转化JM109菌株.以下列步骤纯化表达产物:硫酸铵分级沉淀、阴离子交换、亲和层析和凝胶排阻层析.以凝胶排阻层析测定纯化酶的天然分子量,以邻硝基苯基半乳糖为底物测定其酶学特性.[结果]实现了该酶在JM109菌株中的可溶性表达.其氨基酸序列有一处不同于嗜酸乳酸杆菌NCFM菌株,即其大亚基(LacL)的第512位氨基酸不是组氨酸而是精氨酸.纯化酶比活力为226 U/mg蛋白,天然分子量为96.3±4.6 kDa,最适pH为7,最适温度为49℃,Km和Vmax值分别是:2.18±0.12 mmol/L,273±5 U/mg蛋白.     

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     

Characterization of the cholesterol-reducing activity in a cell-free supernatant of Lactobacillus acidophilus ATCC 43121

This study characterizes the factors responsible for the cholesterol reduction by Lactobacillus acidophilus ATCC 43121. In addition, two-dimensional gel electrophoresis (2-DE) and protein profiling was also used to study the response of ATCC 43121 at the proteome level in the presence of cholesterol. The results show that the cell-free supernatant (CFS) produced by ATCC 43121 in the presence of bile salts could also reduce the cholesterol in the broth, whereas all previous reports have suggested a mechanism by live cells. The active fraction was partially purified by 60% ammonium sulfate precipitation, and subsequent Sephacryl S-100 column chromatography. The molecular weight of the component with cholesterol-reducing activity was estimated to be approximately 12 kDa by SDS-PAGE. These results suggest that the novel protein isolated from CFS may be an important factor in the mechanism for cholesterol reduction by ATCC 43121. In addition, the proteins expressed by ATCC 43121 in the presence of cholesterol micelles were detected by 2-DE, five protein spots with at least a 2.5-fold increase in amounts being identified. The responsible proteins may be involved in the stress-response, translation, and metabolic processes. These results may suggest a new possibility for the mechanism underlying cholesterol reduction by lactic acid bacteria (LAB), differing from the conclusions of previous reports.     

响应面法对微拟球藻产微藻蛋白的发酵条件优化

以稳定期微藻蛋白浓度为评价指标,利用响应面设计对微拟球藻(Nannochloropsis gaditana)的分批发酵条件进行优化。在单因素试验的基础上,选取温度、p H、搅拌速度及通气量为影响因子,采用四因素三水平的Box-Benhnken中心组合法设计试验。结果表明:微拟球藻的最佳发酵条件为温度30℃、p H 6.9、搅拌速度340 r/min以及通气量0.65 vvm,在此优化条件下得到微藻蛋白浓度为6.18 g/L,与模型预测值基本相符,较优化前提高了9.18%。     

响应面法优化生防菌吡咯伯克霍尔德氏菌JK-SH007的发酵工艺

以吡咯伯克霍尔德氏菌Burkholderia pyrrocinia JK-SH007为出发菌株,对其发酵工艺进行优化,以期提高发酵效率.通过筛选试验、最陡爬坡试验和响应面分析确定影响JK-SH007菌株生长最重要两因素为玉米浆和葡萄糖,其最佳浓度分别为13.88 g/L和3.37 g/L.优化后的发酵工艺培养该菌浓度可达1.18×109 CFU/mL,比优化前提高1.35倍,抑菌活性提高28.84％.     

响应面法优化荷叶离褶伞菌丝体产漆酶条件

为了对荷叶离褶伞产漆酶条件进行优化,在单因素实验基础上,通过最陡爬坡实验(PB)对培养基8因素进行筛选,获得影响产漆酶的3个显著性因素:葡萄糖,pH和KH₂PO₄;通过中心组合(CCD)设计及响应面分析确定了最优发酵条件:葡萄糖20.09g/L,酪蛋白1.5g/L,酵母提取物1.5g/L,MgSO₄ 3g/L,CuSO₄ 3.75mg/L,KH₂PO₄ 3.97g/L,pH 4.98,VB₁ 0.1g/L,愈创木酚12mg/L,该条件下,漆酶酶活为829.83U/mL,较未优化对照提高46.6%.     

Optimization of erythritol and glycerol accumulation in conidia of Beauveria bassiana by solid-state fermentation, using response surface methodology

Entomopathogenic fungi are widely produced for use as mycoinsecticides. Therefore, improvement of the shelf life of fungal propagules under good and adverse conditions should be a pre-requisite of their production. In order to improve conidial physiology as well as mycoinsecticide efficiency, culture conditions may be varied. The Doehlert design was used to generate response surfaces with an estimation of the parameters of the quadratic model allowing the study of three different factors at a different number of levels. This experimental design was applied to optimize water activity (a _w), pH, and fermentation time for Beauveria bassiana conidial production and accumulation of polyols in solid-state fermentation. Thus, it was possible to identify the region in the experimental range in which the optimum values of these parameters were simultaneously achieved. Maximal conidia production was achieved at pH 5–6 and a _w=0.999. Under these conditions, polyol accumulation was 3 mg erythritol/g conidia and 29.6 mg glycerol/g conidia. However, maximal polyol accumulation was achieved at pH 4.5 and a _w 0.950; erythritol production increased 33-fold and glycerol production 4.5-fold. Under these conditions conidia production was 1,000 times lower. The possibilities of increasing the quality of the biocontrol agent without neglecting yield are discussed.     

Supplementation of a Lactobacillus acidophilus fermentation product can attenuate the acute phase response following a lipopolysaccharide challenge in weaned pigs

Lactobacillus acidophilus fermentation products have been used to improve the performance of nursery pigs. However, research on the influence of this supplement on health is lacking. This study was designed to determine if feeding a Lactobacillus acidophilus fermentation product to weaned pigs would reduce stress and acute phase responses (APR) following a lipopolysaccharide (LPS) challenge. Pigs (n=30; 6.4±0.1 kg) were individually housed in stainless steel pens with ad libitum access to feed and water. Pigs were weighed upon arrival, assigned to one of three groups (n=10/treatment), and fed for 18 days: (1) Control, fed a non-medicated starter diet; (2) Control diet with the inclusion of a Lactobacillus acidophilus fermentation product at 1 kg/metric ton (SGX1) and (3) Control diet with the inclusion of a Lactobacillus acidophilus fermentation product at 2 kg/metric ton (SGX2). On day 7 pigs were anesthetized for insertion of an i.p. temperature device, and similarly on day 14 for insertion of a jugular catheter. Pigs were challenged i.v. with LPS (25 µg/kg BW) on day 15. Blood samples were collected at 0.5 h (serum) and 1 h (complete blood cell counts) intervals from −2 to 8 h and at 24 h relative to LPS administration at 0 h. Pigs and feeders were weighed on days 7, 14 and 18. The supplemented pigs had increased BW and average daily gain before the challenge. In response to LPS, there was a greater increase in i.p. temperature in Control pigs compared with supplemented pigs. In addition, cortisol was reduced in SGX2 pigs while cortisol was elevated in SGX1 pigs at several time points post-challenge. White blood cells, neutrophils and lymphocytes were decreased in SGX1 and SGX2 compared with Control pigs. Furthermore, the pro-inflammatory cytokine response varied by treatment and dose of treatment. Specifically, serum TNF-α was greatest in SGX2, intermediate in Control, and least in SGX1 pigs, while the magnitude and temporal pattern of IFN-γ in SGX2 pigs was delayed and reduced. In contrast, IL-6 concentrations were reduced in both SGX treatment groups compared with Control pigs. These data demonstrate that different supplementation feed inclusion rates produced differential responses, and that feeding SynGenX to weaned pigs attenuated the APR to an LPS challenge.     

Optimization of fermentation conditions for the production of ethanol from sago starch using response surface methodology

The quantitative effects of temperature, pH and time of fermentation were investigated on simultaneous saccharification and fermentation (SSF) of ethanol from sago starch with glucoamylase (AMG) and Zymomonas mobilis ZM4 using a Box–Wilson central composite design protocol. The SSF process was studied using free enzyme and free cells and it was found that with sago starch, maximum ethanol concentration of 70.68 g/l was obtained using a starch concentration of 140 g/l, which represents an ethanol yield of 97.08%. The optimum conditions for the above yield were found to be a temperature of 36.74 °C, pH of 5.02 and time of fermentation of 17 h. Thus by using the central composite design, it is possible to determine the accurate values of the fermentation parameters where maximum production of ethanol occurs.     

Optimization of Cd2+ removal by the cyanobacterium Synechocystis pevalekii using the response surface methodology

Response surface methodology (RSM) has been used to optimize the critical parameters responsible for higher Cd²⁺ removal by a unicellular cyanobacterium Synechocystis pevalekii. A three-level Box–Behnken factorial design was used to optimize pH, biomass and metal concentration for Cd²⁺ removal. A coefficient of determination (R²) value (0.99), model F-value (86.40) and its low p-value (F < 0.0001) along with lower value of coefficient of variation (5.61%) indicated the fitness of response surface quadratic model during the present study. At optimum pH (6.48), biomass concentration (0.25 mg protein ml^?1) and metal concentration (5 μg ml^?1) the model predicted 4.29 μg ml^?1 Cd²⁺ removal and experimentally, 4.27 μg ml^?1 Cd²⁺ removal was obtained.     

响应面法优化波赛链霉菌JMC 06001发酵培养基

采用响应面法对产生抑菌活性物质的波赛链霉菌（Streptomyces peucetius）菌株JMC 06001的发酵培养基进行优化。首先采用Minnimum Run Equireplicated Res IV设计对初始发酵培养基的8个营养因素进行筛选,获得影响产生抑菌活性物质的3个主要影响因素：葡萄糖、大豆粉和NaCI;然后用最陡爬坡实验快速逼近最大响应区域;最后,结合Box-Behnken设计及响应面分析,确定主要影响因素的最佳浓度,得出该菌株产抑菌活性物质的最优发酵培养基配方为：葡萄糖1．2％,麦芽糖0．7％,蛋白胨0．9％,大豆粉1．4％,NaCl3．7％,CaCO3 0．1％,复合盐A液2．0％,复合盐B液0．1％,起始pH值7．0。用优化后的培养基发酵所得发酵液对敏感指示菌藤黄八叠球菌的抑菌圈直径达31．5mm,与预测值的相对偏差仅为1．59％,与用初始发酵培养基发酵所得发酵液的抑菌效果（抑菌圈直径26．5mm）相比提高了18．9％。     

Inulinase overproduction by a mutant of the marine yeast Pichia guilliermondii using surface response methodology and inulin hydrolysis

In this study, in order to isolate inulinase overproducers from the marine yeast Pichia guilliermondii, its cells were treated by using UV light and LiCl. The mutant M-30 with enhanced inulinase production was obtained and was found to be stable after cultivation for 20 generations. Response surface methodology (RSM) was used to optimize the medium compositions and cultivation conditions for inulinase production by the mutant M-30 in liquid fermentation. Inulin, yeast extract, NaCl, temperature, pH for maximum inulinase production by the mutant M-30 were found to be 20.0 g/l, 5.0 g/l, 20.0 g/l, 28 °C and 6.5, respectively. Under the optimized conditions, 127.7 U/ml of inulinase activity was reached in the liquid culture of the mutant M-30 whereas the predicted maximum inulinase activity of 129.8 U/ml was derived from RSM regression. Under the same conditions, its parent strain only produced 48.1 U/ml of inulinase activity. This is the highest inulinase activity produced by the yeast strains reported so far. We also found that inulin could be actively converted into monosaccharides by the crude inulinase.