Oats tempeh

Oats was used as a substrate in tempeh fermentation. The time needed to obtain sufficient mold growth was at least 30 hours at 31°C (Rhizopus oligosporus NRRL 2710). pH was decreasing during the first 32 hours of incubation reaching pH = 5.30. Fermentation of oats led to an increase in water soluble nitrogen, but it did not change protein nitrogen content. R. oligosporus proteinases of optimum pH = 5.50 are postulated to play an important role in oats tempeh fermentation. When a mixture of oats and soybean (1:1) was used, mold growth was faster and the cake tougher. Mixing cereals with legumes to produce good tempeh is recommended.     

Degradation of stachyose,raffinose, melibiose and sucrose by different tempe-producing Rhizopus fungi

Forty-six strains of tempe-forming Rhizopus species were screened for their ability to grow on raffinose as the sole carbon source. Six of the strains showed good growth and sporulation. These isolates were one Rhizopus oligosporus, one Rhizopus microsporus var. chinensis, three Rhizopus oryzae and one Rhizopus stolonifer. These six moulds and R. oligosporus strain NRRL 2710 were investigated for their metabolism of the raffinose family of -galactoside carbohydrates. Degradation experiments were performed in submerged culture in a medium containing soybean -protein, sodium phytate and either stachyose, raffinose or melibiose. R. oryzae and R. stolonifer completely consumed the tested carbohydrates as carbon source. R. microsporus var. chinensis failed to hydrolyse the -galactosidic bonds of raffinose, stachyose or melibiose, whereas it was able to use sucrose and the fructose moiety of raffinose or stachyose for growth. R. oligosporus NRRL 2710 was unable to hydrolyse any of the tested carbohydrates. The results of the oligosaccharide degradation experiments could be verified during tempe production from soybeans with the selected fungal species.     

Optimization of phytase production by solid substrate fermentation

The production of phytase by three feed-grade filamentous fungi (Aspergillus ficuum NRRL 3135, Mucor racemosus NRRL 1994 and Rhizopus oligosporus NRRL 5905) on four commonly used natural feed ingredients (canola meal, cracked corn, soybean meal, wheat bran) was studied in solid substrate fermentation (SSF). A. ficuum NRRL 3135 had the highest yield [15 IU phytase activity/g dry matter (DM)] on wheat bran. By optimizing the supplementation of wheat bran with starch and (NH₄)₂SO₄, phytase production increased to 25 IU/g DM. Optimization was carried out by Plackett-Burman and central composite experimental designs. Using optimized medium, phytase, phosphatase, alpha-amylase and xylanase production by A. ficuum NRRL 3135 was studied in Erlenmeyer flask and tray SSF. By scaling up SSF from flasks to stationary trays, activities of 20 IU phytase activity/g DM were reproducibly obtained. Electronic Publication     

Linoleic acid, α-linolenic acid,and monolinolenins as antibacterial substances in the heat-processed soybean fermented with Rhizopus oligosporus

ABSTRACT

Antibacterial activities against Staphylococcus aureus and Bacillus subtilis were found in an ethanol fraction of tempe, an Indonesian fermented soybean produced using Rhizopus oligosporus. The ethanol fraction contained free fatty acids, monoglycerides, and fatty acid ethyl esters. Among these substances, linoleic acid and α-linolenic acid exhibited antibacterial activities against S. aureus and B. subtilis, whereas 1-monolinolenin and 2-monolinolenin exhibited antibacterial activity against B. subtilis. The other free fatty acids, 1-monoolein, monolinoleins, ethyl linoleate, and ethyl linolenate did not exhibit bactericidal activities. These results revealed that R. oligosporus produced the long-chain polyunsaturated fatty acids and monolinolenins as antibacterial substances against the Gram-positive bacteria during the fungal growth and fermentation of heat-processed soybean.     

柑橘内生真菌的分离鉴定及其发酵产物对柑橘溃疡病菌的抑制活性

本研究从柑橘抗病品种的健康植株不同组织中分离纯化和鉴定内生真菌,并测定其发酵产物对柑橘溃疡病菌的抑制活性,以明确柑橘抗病品种中内生真菌的组成及其产抗柑橘溃疡病菌活性代谢产物的潜力,为柑橘溃疡病抗菌剂的开发奠定基础。该研究通过组织培养法分离内生真菌,采用形态学和分子生物学方法对其进行鉴定; 基于前期的拮抗预试验结果,选取代表性菌株进行发酵培养,通过乙酸乙酯浸提、真空抽滤、旋转蒸发浓缩制备粗提物; 采用带毒平板涂布法测定不同菌株发酵产物乙酸乙酯提取物对柑橘溃疡病菌的抑制活性。结果表明:(1)共分离得到72株内生真菌,归为2门(Ascomycota、Basidiomycota)、14个属,其中优势属为刺盘孢属(Colletotrichum)、球座菌属(Guignardia)、链格孢属(Alternaria)和镰刀菌属(Fusarium)。(2)不同柑橘品种中内生真菌多样性指数为温州蜜柑(桂林)>沙糖桔(桂林)>沙糖桔(梧州)。(3)不同组织中内生真菌多样性变化因地理位置差异而有所不同,采自桂林的温州蜜柑和沙糖桔均为叶片中的内生真菌的多样性高于枝条,而采自梧州的沙糖桔为叶片中的多样性低于枝条,并且采自梧州的柑橘样品与采自桂林的柑橘样品中的内生真菌相似性低。(4)测定了30株内生真菌乙酸乙酯提取物对柑橘溃疡病菌的抑制活性,其中29株菌株表现出不同程度抑制活性。不同柑橘品种中的优势属的MIC介于0.312 5～10 mg·mL^-1之间,特有属的MIC介于0.156～5 mg·mL^-1,共有属镰刀菌属的MIC介于0.312 5～2.5 mg·mL^-1之间。研究结果表明柑橘抗病品种中内生真菌具有丰富多样性,并且其发酵提取物普遍对柑橘溃疡病菌具有抑制作用。特有属抑菌活性总体优于优势属,共有属镰刀菌属在不同柑橘抗病品种中均具有显著抑菌效果。     

Effects of temperature,water activity and gas atmosphere on mycelial growth of tempe fungi Rhizopus microsporus var. microsporus and R. microsporus var. oligosporus

Rhizopus microsporus var. microsporus and var. oligosporus are used in the manufacture of various Asian fermented foods (tempe, black oncom, sufu). In view of solid-substrate fermentation (SSF) control, mycelial growth of strains of both varieties was tested for sensitivity to fluctuations of temperature, water activity and interstitial gas composition. This was achieved by measuring radial growth as well as biomass dry weight of pre-germinated microcolonies on defined media. The optimum conditions were temperature 40 °C, a _w 0.995 and a gas composition of air for the growth of both strains on a model medium. Whereas radial growth rates of var. microsporus and var. oligosporus were similar, biomass growth rates of var. oligosporus were higher than those of var. microsporus under optimum conditions. The temperature-dependent growth of Rhizopus spp. at a _w > 0.98 could be described by the Ratkowsky Equation. Carbon dioxide (5–10% v/v) inhibited the growth of Rhizopus spp. at non-limiting levels of oxygen. The two strains were able to grow at low (0.5% v/v) oxygen levels, but the mycelial density was rather low. No interrelation of water activity and gas composition was observed, but at high water activity the fungi were more sensitive to changes of temperature. The implications for process control are discussed. This revised version was published online in November 2006 with corrections to the Cover Date.     

Phytic acid content reduction in canola meal by various microorganisms in a solid state fermentation process

Solid state fermentation of canola meal has been carried out for the reduction of its phytic acid content using the following microorganisms: Rhizopus oligosporus NRRL 2990, Aspergillus niger NRC 5765 and NRC 401 121, Aspergillus ficuum NRRL 3135 and a wild Saccharomyces cerevisiae strain. The results showed that all these microorganisms can be used for the reduction of the phytic acid content in the tested material. A. ficuum which completely hydrolyzed the phytic acid in 48 hours was the most efficient. Buffered systems, aeration and an increase in inoculum concentration caused faster and higher reduction of phytic acid content in canola meal.     

Design,Synthesis, Biological Activity Evaluation and Action Mechanism of Myricetin Derivatives Containing Thiazolebisamide

The plant diseases caused by a variety of pathogens such as viruses, bacteria and fungi pose a great threat to global food production and food safety. Therefore, the search for green, efficient and pollution-free pesticides has become an important task. In this article, 23 myricetin derivatives containing thiazolebisamides active groups have been designed and synthesized. Their activities were evaluated by performing in vitro antibacterial and in vivo antiviral assays, microscale thermophoresis (MST) and molecular docking assays. The results of in vivo antiviral assays showed that compounds A4 and A23 exhibited good antiviral activity with EC₅₀ values of 79.0 and 54.1 μg/mL for therapeutic activity and 103.3 and 91.2 μg/mL for protective activity, respectively. The dissociation constants (Kd) values of compounds A4 and A23 against TMV-CP were 0.021 and 0.018 μM, respectively, determined by microscale thermophoresis (MST), which were much smaller than those of the commercial drug ningnanmycin (NNM), which were 2.84 μM. The interaction of compounds A4 , A23 with TMV-CP was further verified at the molecular level. In addition, in vitro antifungal assays of this series of compounds showed that they exhibited some inhibitory activity against a variety of fungi, especially against the phytophthora capsici. Among them, A13 and A20 showed similar inhibitory activity to the control drug azoxystrobin at 100 μg/mL against the phytophthora capsici.     

多脂长喙壳菌次生代谢产物的抑菌活性研究

植物病原真菌是生态系统的重要组成部分,能够代谢产生多种生物活性物质。用纸片法检测多脂长喙壳菌(Ceratocystis adiposa)发酵提取物对13种致病细菌的抑菌活性,并对潜在抗菌活性化合物的热、酸碱和光稳定性进行检测,同时应用OSMAC策略寻找多脂长喙壳菌产抗菌化合物的最佳培养条件。结果表明:多脂长喙壳菌提取物对革兰阳性菌——蜡样芽胞杆菌(Bacillus cereus)、缓慢芽胞杆菌(Bacillus lentus)、藤黄微球菌(Micrococcus luteus)具有抗菌活性,MIC分别为6.25、3.125和1.562 5 mg/m L,抗菌化合物具有较好的耐热、耐酸碱和耐辐射性,培养基种类、培养时间和接种量会影响多脂长喙壳菌抗菌化合物的产生,为多脂长喙壳菌抗菌化合物的开发利用提供参考。     

Influence of solid state fermentation by Trichoderma spp. on solubility,phenolic content,antioxidant, and antimicrobial activities of commercial turmeric

The influence of solid state fermentation (SSF) by Trichoderma spp. on the solubility, total phenolic content, antioxidant, and antibacterial activities of turmeric was determined and compared with unfermented turmeric. The solubility of turmeric was monitored by increase in its phenolic content. The total phenolic content of turmeric extracted by 80% methanol and water after SSF by six species of Trichoderma spp. increased significantly from 2.5 to 11.3–23.3 and from 0.5 to 13.5–20.4 GAE/g DW, respectively. The antioxidant activities of fermented turmeric were enhanced using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid) (ABTS), and ferric ion-reducing antioxidant power (FRAP) assays. The antibacterial activity of fermented turmeric against human-pathogenic bacteria Escherichia coli, Streptococcus agalactiae, Staphylococcus aureus, Entreococcus faecalis, Methicillin-Resistant S. aureus, Klebsiella pneumonia, and Pseudomonas aeruginosae showed a broad spectrum inhibitory effect. In conclusion, the results indicated the potentials of using fermented turmeric as natural antioxidant and antimicrobial material for food applications.     

Structure and biological properties of first row d-transition metal complexes with N-substituted sulfonamides

Cobalt (II), copper (II), nickel (II) and zinc (II) complexes with 2-hydroxy-1-naphthaldehyde derived N-substituted sulfonamides have been synthesized and the nature of bonding and structure of compounds have been deduced from physical, analytical and spectral (IR, ¹H NMR, ¹³C NMR, Mass and electronic) data. An octahedral geometry has been suggested for the complexes. Complexes along with the ligands were assessed for their antibacterial and antifungal activities on different species of pathogenic bacteria and fungi. The results revealed the ligands to possess moderate to significant antibacterial activity which was, in many cases, enhanced on chelation. Similar results were observed for antifungal activity. Brine shrimp bioassay was also carried out for in vitro cytotoxic properties against Artemia salina.     

Changes in the antibiotic production by co-culture of Rhizopus peka P8 and Bacillus subtilis IFO3335

The co-culture of Bacillus subtilis IFO 3335 with Rhizopus peka P8 or Rhizopus oligosporus P12 in liquid medium was found to increase production of antibiotic activity and to alter the spectrum of activity relative to the pure cultures. However, a mixed culture of Rhizopus arrhizus P7 and Rhizopus oryzae P17 did not produce antibiotic activity. The concentration, ratio, and time of addition of B. subtilis to the R. peka culture was found to influence antibiotic yields. Solid-state fermentations using mixed cultures of R. peka and B. subtilis were investigated. The growth of Escherichia coli IFO 3792 as a target bacterium was inhibited by the mixed culture. These results suggest the possibility of biopreservation of fermented foods by novel co-culture systems.     

地衣型真菌次级代谢产物抗菌活性初步研究

地衣是一种传统的民族药物,能产生多种具有活性的物质。该研究对地衣型真菌(Xanthoria elegans,Myelochroa indica,Ramalina peruviana,Cladonia macilenta,Nephromopsis pallescens,Cladonia coccifera)进行液体培养,2个月后,培养液用乙酸乙酯萃取后获得初提物。该研究采用抑菌圈法评价地衣型真菌初提物对7种致病细菌(Bacillus subtilis,Bacillus cereus,Vibrio parahaemolyticus,Straphylococcus haemolyticus,Pseudomonas aeruginosa,Staphylococcus aureus,Micrococcus luteus)的抗菌活性,并测定最低抑菌浓度(MIC)。结果表明:6种地衣型真菌的初提物均具有一定的抗菌活性,且不同培养基对地衣型真菌产生抗菌物质有显著影响。其中,R.peruviana在MY液体培养基中所产生的次级代谢产物对金黄色葡萄球菌、藤黄微球菌、溶血性葡萄球菌、铜尿假单胞菌具有抑制效果,但在YMG培养基中所得初提物对供试7种致病细菌不具有抑菌效果。X.elegans在YMG培养基中所得初提物对枯草芽孢杆菌具有明显抗菌活性,其抑菌圈直径可达17.77 mm。该研究证实不同地衣型真菌液体培养初提物具有抗菌活性,不同的培养基也直接影响地衣型真菌抗菌效果。该研究结果为地衣型真菌的进一步研究及民族药的开发利用奠定了基础。     

Suppression of Plasma Cholesterol Elevation by Okara Tempe in Rats

Okara Tempe (OT), an Indonesian fermented traditional food, which is the fermented okara (insoluble residues of homogenized soybean, OC) by Rhizopus oligosporus, and which is interested in as a new high fiber and low energy soybean foodstuff. In this study, the effects of protein and dietary fiber (DF) of OT on sterol metabolism in rats were investigated. When rats were fed by OT or casein as protein source, the cholesterol and bile acid levels in plasma was significantly lower in OT fed group than in casein fed group. When rats were fed by OT or OC as DF source, in OT fed group, the cholesterol and bile acid levels in plasma was similar to them in OC fed group, but the cholesterol level in liver was lower than it in OC fed group, and the excretion of cholesterol and bile acid in feces was larger than in OC fed group. These results suggest that the cholesterol lowering action of OT in plasma would arise from the complementary action of protein and water soluble DF in OT.     

Synthesis and in Vitro Antimicrobial Activity Screening of New 3‐Acetyl‐2,5‐disubstituted‐1,3,4‐oxadiazoline Derivatives

Thirteen new 3‐acetyl‐2,5‐disubstituted‐1,3,4‐oxadiazoline derivatives were synthesized from corresponding hydrazide‐hydrazones of isonicotinic acid in the reaction with acetic anhydride. The obtained compounds were identified with the use of spectral methods (IR, ¹H‐NMR, ¹³C‐NMR, MS). In vitro antimicrobial activity screening of synthesized compounds against a panel of bacteria and fungi revealed interesting antibacterial and antifungal activity of tested 1,3,4‐oxadiazoline derivatives, which is comparable to that of commonly used antimicrobial agents.     

Genetically modified soybeans: false-positive detection in fermented natural soybean (tempe)

Tempe was prepared using mixtures of natural soybean and genetically modified Roundup Ready (RUR) soybean fermented with natural Rhizopus sp. The amount of RUR soybean was quantified using an ELISA plate test. The RUR signal decreased during fermentation. In the control experiments on fermentation of non-RUR soybean, the tempe gave a false-positive RUR signal. The cross-reacting substance was generated only in non-RUR soybean during fermentation by Rhizopus sp., Rhizopus oligosporus, R. oryzae, Mucor rouxii and Aspergillus awamori.     

Antibacterial activity of<Emphasis Type="Italic">Ulva lactuca</Emphasis> against methicillin-resistant<Emphasis Type="Italic">Staphylococcus aureus</Emphasis> (MRSA)

Thein vitro antimicrobial activity of the marine green algaeUlva lactuca was examined against gram-positive bacteria, gram-negative bacteria, and a fungus. The ethyl-ether extract of algae exhibited a broad-spectrum of antibacterial activity. but not antifungal activity againstCandida albicans. In particular, theU. lactuca extract showed strong activity aganst the bacterium methicillin-resistantStaphylococcus aureus (MRSA). This result confirms the potential use of seaweed extracts as a source of antibacterial compounds or as a health-promoting food for aquaculture.     

Synthesis and biological activities of new hydrazide derivatives

The synthesis of a new series of imidazo[1,2-a]pyrazine-2-carboxylic acid arylidene-hydrazides is described. The chemical structures of the compounds were elucidated by IR, ¹H-NMR, FAB⁺-MS spectral data. Their biological activity against various bacteria, fungi species, and Mycobacterium tuberculosis was investigated. Antibacterial activity was measured against Escherichia coli (NRRL B-3704), Staphylococcus aureus (NRRL B-767), Salmonella typhimurium (NRRL B-4420), Proteus vulgaris (NRLL B-123), Enterococcus faecalis (isolated obtained from Faculty of Medicine Osmangazi University, Eskisehir, Turkey), Pseudomonas aeruginosa (NRRL B-23 27853), Klebsiella spp. (isolated obtained from Faculty of Medicine Osmangazi University, Eskisehir, Turkey), while antifungal activity was evaluated against Candida albicans (isolates obtained from Osmangazi Uni. Fac.of Medicine), Candida glabrata (isolates obtained from Osmangazi Uni. Fac.of Medicine). Compounds were also evaluated for antituberculosis activity against Mycobacterium tuberculosis H₃₇Rv using the BACTEC 460 radiometric system and BACTEC 12B medium. The compounds showed moderate inhibitor effects against human pathogenic microorganisms., whereas the preliminary results indicated that all of the tested compounds were inactive against Mycobacterium tuberculosis H₃₇Rv.     

Structure-function relationships of the antibacterial activity of phenolic acids and their metabolism by lactic acid bacteria

Aims: To determine structure–function relationships of antibacterial phenolic acids and their metabolites produced by lactic acid bacteria (LAB). Methods and Results: Minimum inhibitory concentrations (MICs) of 6 hydroxybenzoic and 6 hydroxycinnamic acids were determined with Lactobacillus plantarum, Lactobacillus hammesii, Escherichia coli and Bacillus subtilis as indicator strains. The antibacterial activity of phenolic acids increased at lower pH. A decreasing number of hydroxyl groups enhanced the activity of hydroxybenzoic acids, but had minor effects on hydroxycinnamic acids. Substitution of hydroxyl groups with methoxy groups increased the activity of hydroxybenzoic, but not of hydroxycinnamic, acid. Metabolism of chlorogenic, caffeic, p‐coumaric, ferulic, protocatechuic or p‐hydroxybenzoic acids by L. plantarum, L. hammesii, Lactobacillus fermentum and Lactobacillus reuteri was analysed by LC‐DAD‐MS. Furthermore, MICs of substrates and metabolites were compared. Decarboxylated and/or reduced metabolites of phenolic acids had a lower activity than the substrates. Strain‐specific metabolism of phenolic acids generally corresponded to resistance. Conclusions: The influence of lipophilicity on the antibacterial activity of hydroxybenzoic acids is stronger than that of hydroxycinnamic acids. Metabolism of phenolic acids by LAB detoxifies phenolic acids. Significance and Impact of the Study: Results allow the targeted selection of plant extracts for food preservation, and selection of starter cultures for fermented products.     

饲用微生物的分离鉴定及其对杏鲍菇菌糠发酵的效果

【目的】菌糠的营养素含量齐全,但纤维素含量过高是阻碍其饲料化利用的主要因素。故本研究筛选适合于发酵杏鲍菇菌糠的微生物菌株,以改善其饲用品质。【方法】首先,本研究采用纤维素-刚果红、苯胺蓝和MRS-Ca (De Man, Rogosa, Sharpe-Ca)筛选培养基,结合纤维素、木质素酶活力及抑菌活性的测定,从EM (effective microorganisms)原液发酵的杏鲍菇菌糠中分离筛选具有较强纤维素、木质素降解能力及抑菌能力的细菌/真菌。通过细菌16S rRNA和真菌18S rDNA基因序列分析确定菌株所属种属。其次,将筛选出的菌株菌液等体积混合制成复合菌剂用于固态发酵杏鲍菇菌糠。测定不同发酵时长菌糠营养成分含量以确定最佳发酵时间,并与相同工艺条件下EM原液发酵的杏鲍菇菌糠进行饲用品质比较。【结果】筛选并鉴定得到纤维素酶活性较高的特基拉芽孢杆菌(Bacillus tequilensis)菌株P11、发酵毕赤酵母(Pichia fermentans)菌株R8和马克斯克鲁维应变酵母(Kluyveromyces marxianus)菌株MU5;木质素酶活性较高的解淀粉芽孢杆菌(Bacillus amyloliquefaciens subsp.plantarum)菌株MU7;抑菌活性较高的类肠膜魏斯氏菌(Weissella paramesenteroides)菌株R4和乳酸片球菌(Pediococcus acidilactici)菌株R9。使用以上菌株复合发酵杏鲍菇菌糠7 d后,各项指标达到稳定。与EM原液发酵的杏鲍菇菌糠相比,复合菌剂发酵杏鲍菇菌糠的NDF和ADF分别显著降低了19.6%和21.44%(P0.05);CP (crude protein)、CA (crude ash)和EE (ether extract)含量分别显著提高了10.44%、5.26%和123.53%(P0.05)。【结论】本研究筛选得到的芽孢杆菌、酵母菌和乳酸菌优势菌株复合后用于发酵杏鲍菇菌糠可以很好地改善其饲用品质,效果优于生产中常用市售EM原液。