Effect of gamma-aminobutyric acid-enriched tempeh-like fermented soybean (GABA-Tempeh) on the blood pressure of spontaneously hypertensive rats

GABA-enriched tempeh-like fermented soybean (GABA-tempeh) was supplemented to the AIN-76 diet and fed for 2 months to spontaneously hypertensive rats (SHRs), an animal model of spontaneously developed hypertension, to compare the antihypertensive activity with that of authentic GABA. The elevation of systolic blood pressure in SHRs was significantly retarded in the GABA-tempeh group as well as that with authentic GABA when compared with the controls, and the effect lasted for two months of the feeding period. The blood urea nitrogen level tended to be higher in the control group than in the GABA-supplemented groups. On the other hand, no effect was apparent on the plasma levels of cholesterol, triacylglycerol and glucose, or on the urinary excretion of Na and K.     

富马酸生产菌少根根霉的诱变筛选

以实验室原少根根霉为出发菌种,通过紫外线和LiCl诱变处理,发现当紫外线照射时间为3min,并在质量分数4％LiCl的平板中培养,可诱变出富马酸高产菌。利用溴甲酚绿加塑料小管的平板进行初筛,其生成的富马酸通过塑料小管底部渗透到指示培养基中,产生变色圈,根据变色圈大小可初步判断诱变株的产酸能力,大大缩短了筛选时间。在葡萄糖质量浓度为80g/L时,诱变后的3#菌种在发酵72h后能产生55．02g/L的富马酸,比原菌种的富马酸产量提高了2．49倍。     

Improvement of clavulanic acid production by Streptomyces clavuligerus in medium containing soybean derivatives

The effect of the nitrogen source in the production medium on the level of clavulanic acid production by Streptomyces clavuligerus has been investigated. Batch cultures using two types of synthetic culture medium and two types of complex culture medium containing soybean derivatives were employed. To allow comparison of the various media, all of them were formulated with 4.0 g total nitrogen/l. It was observed that the production of clavulanic acid using synthetic medium reached values slightly greater than those usually found in the literature. However, in trials with complex media, it was found that when Samprosoy 90NB (protein extract of soybean) was utilized, production of clavulanic acid went up to 920 mg/l, twice as high as when soy meal was used, and notably higher than values reported in the literature (300–500 mg/l) for complex medium.     

Physiological restriction of the L-lactic acid production by Rhizopus arrhizus

The influence of basic physiological factors on the quality of inocula and L(+)-lactic acid production by Rhizopus arrhizus CCM 81 09 were studied. The most effective preparation of the spores (5 × 10⁷ spores/ml) and subsequent good lactate production was achieved on the agar medium with soil extract and malt agar. The optimum initial amount of active spores for inoculation was 10³–10⁴ spores/ml. The preparation of inoculum required intensive stirring with lower aeration and pH maintained in the range from 4.8 to 6.0 by the addition of CaCO₃. The maximum yield of lactic acid production was achieved by using 5% (v/v) of 24-h-old inoculum. The intensity of lactic acid production in the inoculum was proportional to its production in the subsequent steps of fermentation and can be used as a fast control of the physiological state of the producers.     

A new post-treatment system for anaerobic effluents containing a high Ca2+ content

A novel reactor concept has been developed that combines Ca²⁺ removal and BOD conversion under mesophilic (30 °C ) as well as under thermophilic (55 °C ) conditions. Soluble Ca²⁺, present in many industrial wastewaters, precipitates as a result of forced aeration in the aerobic bioreactor. The CaCO₃ precipitates, in turn, act as a carrier material for biofilm growth. This resulted in dense rapidly settling sludge granules covered with a biofilm on the surface. These sludge characteristics facilitate the application of hydraulic retention times of 1 h while maintaining a high biological activity in the reactor.     

Phytic acid changes in soybeans fermented by traditional inoculum and six strains of Rhizopus oligosporus

Tempeh was prepared from Delmar variety soybeans inoculated with the traditional Indonesian inoculum (usar) and six pure culture strains of Rhizopus oligosporus. The strains BTU3K1 and CT11K2 produced the best quality tempeh. The phytic acid content of soybeans was reduced from 1mD07% in whole dry soybeans to 0mD67–0mD75% in tempeh. Most mould strains did not have a significantly different effect on reducing the phytic acid content in tempeh, although the traditional inoculum was significantly different to strains CTU7K2, BTU3K1, BT1K4 and CT11K2.     

硫酸锌(ZnSO4)对米根霉发酵产乳酸的影响

[目的]为了了解无机盐与米根霉L-乳酸代谢之间的关系,提高米根霉菌株RLC41-6发酵产L-乳酸的产率与质量,研究了ZnSO4浓度与菌株乳酸代谢和细胞内乳酸脱氢酶活性的关系.[方法]在米根霉培养基中加入不同浓度ZnSO4,经过36℃培养36 h后,应用HPLC-反相色谱法测定产物中的L-乳酸含量,并利用活性PAGE分析法测定细胞内乳酸脱氢酶的活性和组成.[结果]实验结果显示,ZnSO4对除LDH1之外的其它几条同工酶都有促进作用,尤其对LDH4,LDH5作用明显,当ZnSO4浓度大于0.02％时,LDH4,LDH5达到最大水平,同时高浓度的锌离子在体外抑制了LDH的活性.当ZnSO4浓度为0.02％时LDH酶活达到最大200 U/mL,HPLC图谱表明,此时发酵产物的只有L-乳酸,且产量达到最大137g/L,乳酸转化率为91％.[结论]Zn+会影响米根霉的乳酸代谢过程,并导致发酵过程中产物类型的变化,合适浓度的ZnSO4在米根霉代谢产乳酸的过程中,提高了乳酸脱氢酶LDH的表达,抑制丙酮酸进入苹果酸和富马酸途径,从而有利于提高葡萄糖到乳酸的代谢.     

Optimization of fumaric acid production from potato flour by Rhizopus arrhizus

Summary Fumaric acid production by Rhizopus arrhizus from potato flour was studied at different initial substrate concentrations (S), C/N ratios and fermentation times (t f) in a composite design experiment. By using response surface methodology and canonical analysis, the experimental values of fumaric acid and mycelial biomass yields and productivity were fitted to the only statistically significant factors with mean percentage errors of 11, 26 and 13%, respectively. Owing to the limited statistical significance of the C/N ratio, it was possible to determine the values of S (25–50 g/l of glucose equivalent) and t f(44–100 h) associated with fumaric acid yields ranging from 60 to 75% and productivities varying from 6 to 8.4 g/l per day. Since such results were in quite good agreement with previous experiments carried out on other starchy materials, the above operating conditions might be used to minimize fumaric acid production costs as a function of the feed-stock used. Offsprint requests to: M. Moresi     

Development of a low pH fermentation strategy for fumaric acid production by Rhizopus oryzae

Dicarboxylic acids that are produced from renewable resources are becoming attractive building blocks for the polymers industry. In this respect, fumaric acid is very interesting. Its low aqueous solubility facilitates product recovery. To avoid excessive waste salt production during downstream processing, a low pH for fumaric acid fermentation will be beneficial. Studying the influence of pH, working volume and shaking frequency on cell cultivation helped us to identify the best conditions to obtain appropriate pellet morphologies of a wild type strain of Rhizopus oryzae. Using these pellets, the effects of pH and CO(2) addition were studied to determine the best conditions to produce fumaric acid in batch fermentations under nitrogen-limited conditions with glucose as carbon source. Decreasing either the fermentation pH below 5 or increasing the CO(2) content of the inlet air above 10% was unfavourable for the cell-specific productivity, fumaric acid yield, and fumaric acid titer. However, switching off the pH control late in the batch phase did not affect these performance parameters and allowed achieving pH of 3.6. A concentration of 20 gL(-1) of fumaric acid was obtained at pH 3.6 while the average cell mass specific productivity and fumaric acid yield were the same as at pH 5.0. Consequently, relatively modest amounts of inorganic base were required for pH control, while recovery of the acid should be relatively easy at pH 3.6.     

Enhanced production of Scenedesmus spp. (green microalgae) using a new medium containing fermented swine wastewater

Fermented swine urine (3%) (v/v) was added to a control medium (CT), named KEP I, and an aquatic microalgal culture (10% Bold's Basal Medium) for growing mixed Scenedesmus species. During a two-month period, the KEP I medium effected, the delayed onset of the stationary phase of cell division in a batch culture. After 31 days, of culturing, the growth rate (3-fold), dry weight (2.6-fold) and amino acid levels (2.7-fold), and secondary metabolites including chlorophyll a (2.1-fold), astaxanthin (2.8-fold), lutein (2.7-fold) and alpha (greater than 30-fold) and beta-carotene (greater than 5-fold) increased a greater degree in Scenedesmus grown in KEP I medium than in CT medium. Total lipids were much less in cells grown in KEP I than those grown in CT. An increased quantum yield of photosystem II of the aquatic microalgae. The KEP I medium should improve the cost efficiency of industrial mass batch cultures for CO(2) sequestration, bioremediation, phytonutrients, agricultural fertilizers, and microalgal stock for the species preservation of aquaculture strains for use in young fish feed. It may also serve to attenuate negative environmental impact via the recycling of animal wastewater.     

Comparison of fumaric acid production by Rhizopus oryzae using different neutralizing agents

Fumaric acid fermentation in a 10-L bubble column fermenter using different neutralizing agents [CaCO(3), Ca(OH)(2), NaHCO(3)] by Rhizopus oryzae ATCC 20344 was examined. It was found that in the fermentation using CaCO(3 )as the neutralizing agent the highest fumaric acid weight yield and volumetric productivity were obtained, 53.4% and 1.03 g/L x h(-1) respectively. In the NaHCO(3) case, the fumaric acid weight yield and volumetric productivity were 33.7% and 0.69 g/L x h(-1), respectively, much lower than the CaCO(3) case. However, the NaHCO(3) alternative has advantages of cell reuse and simple downstream processing because of the high solubility of sodium fumarate. These advantages may offset the disadvantages of using NaHCO(3) as the neutralizing agent, and the overall fumaric acid weight yield and volumetric productivity will increase.     

Production of lean beef containing a high content of trans-10, cis-12 conjugated linoleic acid by feeding a high-temperature-micro-time-treated diet with extruded soybean

The effects were observed of feeding a high-temperature-micro-time (HTMT)-treated diet of high-quality extruded soybean (ESB) on trans-10, cis-12 conjugated linoleic acid (CLA) incorporation in intra-muscular fat and on the lipid metabolism of twelve Holstein steers. The animals were randomly allocated to three groups, the control group being fed on a normal diet, and the other two groups being fed on a diet containing high-quality ESB with or without the HTMT treatment. The experimental period was four months. The content of total CLA in both the HTMT and non-HTMT-treated diets was higher than that in the control diet (P<0.05). The concentration of trans-10, cis-12 CLA was significantly higher in the HTMT-treated diet than in the non-treated diets at P<0.05, and the HTMT-treatment decreased the intra-muscular fat content (P<0.05). The expression of fatty acid synthase (FAS) and the plasma insulin-like growth factor-1 (IGF-1) level in the HTMT-treated group were lower than those in the control group (P<0.05). Lipoprotein lipase (LPL) mRNA level in the adipose tissue was lower in the non-HTMT-treated group than in the control (P<0.05). These results show that the HTMT treatment increased the level of trans-10, cis-12 CLA in the intra-muscular fat. This increased level of trans-10, cis-12 CLA may inhibit lipogenesis in the intra-muscular fat of Holstein steers.     

Medium optimization for production of gamma-aminobutyric acid by Lactobacillus brevis NCL912

Production of gamma-aminobutyric acid (GABA) was carried out in Erlenmeyer flasks by Lactobacillus brevis NCL912. Traditional methods were first adopted to select the key factors that impact the GABA production to preliminarily determine the suitable concentration ranges of the key factors. It was found that glucose, soya peptone, Tween-80 and MnSO₄·4H₂O were the key factors affecting GABA production. Then, response surface methodology was applied to analyze the optimum contents of the four key factors in the medium, and the production of GABA was predicted as 349.69 mM under the optimized conditions with this model. Afterward, the experiment was performed under the optimized conditions, and the yield of GABA reached 345.83 mM, which was 130% higher than the initial medium. The results showed that experimental yield and predicted values of GABA yield were in good agreement.     

D-homoandrostanes. 4. The incubation of some D-homo-5 alpha-androstanes with Rhizopus nigricans

Nine dioxygenated D-homoandrostanes were incubated with Rhizopus nigricans to investigate the effect of D-ring modification on microbiological hydroxylation. Structure determination of the products by NMR spectroscopy, and in certain cases independent synthesis of their oxidised products, showed that in contrast to 5 alpha-androstanes the majority of the compounds were hydroxylated in the "reverse" mode, and only D-homo-5 alpha-androstane-3,17-dione was hydroxylated in the "normal" mode to any extent. Stereospecific ring D-hydroxylation at C(17 alpha) was observed for both D-homo-5 alpha-androstane-3,6- and 3,7-diones.     

Influence of carbohydrates and polyols on l-lactic acid production and fatty acid formation by Rhizopus arrhizus

Growth and l-lactic acid production on 24 different carbohydrates and polyols (glycerol, mannitol and sorbitol) by Rhizopus arrhizus CCM 8109 were determined. The d- but not the l-forms of xylose, fructose, galactose, mannose, glucose, cellobiose, maltose and sucrose and partially hydrolysed starch were converted to l-lactic acid. Changes in lipid formation and fatty acid composition were detected in biomass grown on the different sugars. In the presence of polyols, growth and considerable production of lipids were observed with little or no lactate production. Invertase was mainly associated with the mycelium during growth on sucrose, whereas glucoamylase and -amylase were produced extracellularly during growth on starch.The authors are with the Department of Biochemical Technology, Faculty of Chemical Technology, Slovak Polytechnical University, Radlinského 9, SK-812 37 Bratislava, Slovak Republic     

Optimization of fumaric acid production by Rhizopus delemar based on the morphology formation

The effects of temperature, agitation rate and medium composition, including concentrations of glucose, soybean peptone, and inorganic ions, on pellet formation and pellet diameter of Rhizopus delemar (Rhizopus oryzae) NRRL1526 during pre-culture were studied. Inorganic ions and soybean peptone had negative and positive effects on pellet formation, respectively. The initial glucose and soybean peptone concentrations directly affected pellet diameter. Within a certain range, pellet diameter decreased with increased initial substrate concentrations; however, above this range there was an opposite trend. Thus, optimal concentrations of substrate during pre-culture were beneficial for producing small pellets of R. delemar. Furthermore, dry cell mass and yield of fumaric acid tended to increase with decreased pellet diameter. Based on the pellet morphology optimization, the final fumaric acid concentration was improved by 46.13% when fermented in a flask and 31.82% in stirred bioreactor tank fermentation.     

Citric acid production by recycling its wastewater treated with anaerobic digestion and nanofiltration

We have developed an integrated citric acid-methane fermentation process to solve the problem of wastewater pollution in the citric acid industry. Citric acid wastewater was initially treated by anaerobic digestion. After subsequent ultrafiltration and nanofiltration, the anaerobic digestion effluent (ADE) could be recycled as process water for the next fermentation, maintaining excellent citric acid production efficiency while eliminating wastewater discharge and reducing water consumption. Untreated ADE was not suitable for direct recycling. The effects on citric acid fermentation of components in the ADE were investigated. Production was inhibited when Na⁺ and Mg²⁺ concentrations in recycled ADE were >200 mg/L and >40 mg/L, respectively. This problem was resolved by treating the ADE using ultrafiltration and nanofiltration to reduce Na⁺ and Mg²⁺ concentrations to acceptable levels. Our results prove the technical feasibility of cleaner production in the citric acid industry and provide a strategy for management of wastewater in other submerged fermentation industries.