Efficient production of L-(+)-lactic acid from raw starch by Streptococcus bovis 148

Streptococcus bovis 148 was found to produce L-(+)-lactic acid directly from soluble and raw starch substrates at pH 6.0. Productivity was highest at 37 degrees C, with 14.7 g/l lactic acid produced from 20 g/l raw starch. The yield and optical purity of L-lactic acid were 0.88 and 95.6%, respectively.     

米根霉发酵木薯淀粉产L-乳酸的工艺优化

以培养基配方（糖化液、蛋白胨、酵母膏、麦芽粉添加量）和培养条件（培养温度、pH、培养时间、接种量）的单因素试验结果为 依据,选取糖化液质量分数、培养时间、pH和培养温度4因素,以发酵液中L-乳酸含量为评价指标,基于Box-Behnken试验设计响应面 法优化了米根霉发酵木薯淀粉产L-乳酸的发酵工艺参数。 结果表明,最优发酵工艺参数为糖化液26%、蛋白胨6 g/L、酵母浸膏4 g/L、 麦芽粉10 g/L、KH2PO4 0.3 g/L、MgSO·4 7H2O 0.4 g/L、ZnSO4·7H2O 0.3 g/L、CaCO3 45 g/L、培养时间80 h、培养温度29 ℃、初始pH 5.5、接 种量6%。 该优化条件下,发酵液中L-乳酸的含量可达84.33 g/L,发酵液中葡萄糖对L-乳酸的转化率为71.34%,其光学纯度为75.62%, 比旋光度为+2.12。     

双咪唑磺酸型离子液体催化煎炸废弃油制备生物柴油

为高效环保地制备生物柴油,通过三步法合成了一系列HSO4HSO3-C3\[MIM\]Cn\[MIM\]C3-HSO3HSO4(简写为CnMSS,n=2~6)双咪唑磺酸型离子液体,对其催化酯交换反应的性能进行了探究,并对离子活性最强的离子液体进行了核磁共振表征。以该离子液体为催化剂,通过单因素实验对三油酸甘油酯模型反应条件进行优化,并在此基础上采用正交实验优化煎炸废弃油制备生物柴油的工艺条件,同时对生物柴油产品进行了红外光谱和核磁共振表征。结果表明：离子液体C5MSS的催化性能最强;在醇油摩尔比18∶?1、反应时间8 h、反应温度100?℃、催化剂用量8%（以三油酸甘油酯质量计）条件下,油酸甲酯产率为91.18%,且该离子液体重复使用7次油酸甲酯产率仍然能够达到83%以上。煎炸废弃油制备生物柴油的最优工艺条件为醇油摩尔比18∶?1、反应温度80?℃、反应时间9 h、催化剂用量10%（以煎炸废弃油质量计）,在此条件下生物柴油的产率可达9860%。红外光谱和核磁共振表征结果表明反应生成了脂肪酸甲酯,且酯交换反应比较彻底。     

Production of hyaluronic acid from Streptococcus zooepidemicus MTCC 3523 and its wound healing activity

Exopolysaccharide produced and purified from Streptococcus zooepidemicus MTCC 3523 was identified as hyaluronic acid (HA) based on IR and NMR spectroscopy while its Mw was found to be 5.38 × 10(5)Da. HA produced passed bacterial endotoxin test and showed significant wound healing activity in Wistar rats on 12th and 16th day.     

Open L-lactic acid fermentation of food refuse using thermophilic Bacillus coagulans and fluorescence in situ hybridization analysis of microflora

In the production of commercially useful poly-L-lactic acid plastic from biomass wastes, a feasible fermentation process to produce optically active L-lactic acid would be required. Here, model kitchen refuse (MKR) was inoculated with Bacillus coagulans NBRC12583 under nonsterilized openculture conditions. At temperatures below 45 degrees C, a racemic mixture of D- and L-lactic acids was accumulated, whereas only L-lactic acid was selectively accumulated by incubation at 50-65 degrees C. At 45 degrees C, the results of fermentation could not be consistently reproduced. To analyze microflora in this type of mixed culture system, whole-cell fluorescence in situ hybridization (FISH) using 16S rRNA-targeted oligonucleotide probes for B. coagulans, Bcoa191, and LAC722(L), a group-specific probe for a wide range of mesophilic lactic acid bacteria was applied. The dominancy of mesophilic lactic acid bacteria at lower temperatures, and that of B. coagulans at higher temperatures were confirmed. By using a saccharified liquid of collected kitchen refuse, 86 g/l of L-lactic acid was accumulated under nonsterile conditions by a 5-d incubation at 55 degrees C, pH 6.5, with 53% carbon yield and 97% optical purity. To conclude, high temperature open lactic acid fermentation is a simple and promising method for producing high-grade L-lactic acid from biomass waste, and FISH analysis of such mixed-culture systems is helpful for monitoring the microflora in these cultures.     

高效液相色谱法测定发酵液中聚苹果酸方法的建立

采用高效液相法在Prevail C18色谱柱(4.6mm×250mm,4μm)上定量测定发酵生产的聚苹果酸,流动相为乙腈和0.025mol/L磷酸二氢钾混合溶液(用磷酸调pH2.5)(v∶v=5∶95),流速为1.0mL/min,检测波长为210nm,柱温为25℃。发酵液经离心、水解处理后进样,4min可以将其中的L-苹果酸完全分离定量。方法的回收率为98.84%～101.47%,RSD为1.35%～1.72%。实验结果表明,该法是测定发酵液中聚苹果酸的快速、有效的定量分析方法。     

Production of -aminobutyric acid (GABA) by Lactobacillus paracasei isolated from traditional fermented foods

Lactobacillus strains that accumulated γ-aminobutyric acid (GABA) in culture medium were screened to determine strains with high GABA-producing ability. One strain, NFRI 7415, which was isolated from a Japanese traditional fermented fish (funa-sushi), showed the highest GABA-producing ability among the screened strains. Identification tests (i.e., 16S rDNA sequencing and sugar assimilation ability) indicated that NFRI 7415 belongs to Lb. paracasei. The GABA production was further improved by the addition of pyridoxal phosphate to the culture medium and pH regulation of culture medium at pH 5.0. Under optimal cultivation conditions, strain NFRI 7415 produced GABA at a concentration of 302 mm when the glutamate concentration in the culture medium was 500 mm.     

Variation in short chain fatty acid and ethanol concentration resulting from the natural fermentation of wheat and barley for inclusion in liquid diets for pigs

Fifty‐six samples of wheat and 44 samples of barley were taken, at harvest, from locations across the UK. Lactic acid bacteria (LAB) and yeasts were enumerated before the samples were ground. Following grinding, triplicate 30‐g samples of each cereal were mixed with sterile distilled water and incubated at 30, 35 or 40 °C. Samples were taken immediately after mixing and at 24‐h intervals for analysis of short‐chain fatty acids (SCFA) and ethanol by isocratic ion‐exclusion liquid chromatography. The number of LAB and yeasts present in samples ranged from 0 to 5.0 (mean 2.25 ± 1.31) and 3.30 to 6.25 (mean 4.96 ± 0.74) log₁₀ colony‐forming units (cfu) ml^?1 respectively. At 30 °C the mean concentrations (mmol l^?1) of SCFAs and ethanol were, lactic acid 59.6 ± 40.0 (range 0.14–134.9), acetic acid 23.2 ± 11.1 (range 2.9–51.4), butyric acid 17.2 ± 16.8 (range 0.0–62.2) and ethanol 15.0 ± 9.0 (range 4.6–53.7) respectively. After fermentation for 24 h only 9 of 300 fermentations produced more than 75 mmol l^?1 lactic acid, which has previously been demonstrated to prevent the growth of Salmonella in liquid pig feed. Fermenting at 35 or 40 °C had no effect on lactic acid concentration but significantly (p < 0.001) increased the concentrations of acetic and butyric acids and ethanol. These results indicate that natural fermentation cannot be relied upon to produce levels of SCFAs that will prevent the proliferation of enteropathogens. Copyright © 2004 Society of Chemical Industry     

Efficient production of fatty acid methyl ester from waste activated bleaching earth using diesel oil as organic solvent

Fatty acid methyl ester (FAME) production from waste activated bleaching earth (ABE) discarded by the crude oil refining industry was investigated using fossil fuel as a solvent in the esterification of triglycerides. Lipase from Candida cylindracea showed the highest stability in diesel oil. Using diesel oil as a solvent, 3 h was sufficient to obtain a yield of approximately 100% of FAME in the presence of 10% lipase from waste ABE. Kerosene was also a good solvent in the esterification of triglycerides embedded in the waste ABE. Fuel analysis showed that the FAME produced using diesel oil as a solvent complied with the Japanese diesel standard and the 10% residual carbon amount was lower than that of FAME produced using other solvents. Use of diesel oil as solvent in the FAME production from the waste ABE simplified the process, because there was no need to separate the organic solvent from the FAME-solvent mixture. These results demonstrate a promising reutilization method for the production of FAME, for use as a biodiesel, from industrial waste resources containing waste vegetable oils.     

双柱串联反相高效液相色谱测定苹果醋中的有机酸

建立了双柱串联高效液相色谱紫外检测器测定苹果醋中6种有机酸的测定方法。样品用水稀释后采用双C18色谱柱(4.6 mm×250 mm×5μm)进行色谱分离,流动相为0.01 mol/L的磷酸氢二铵溶液(p H2.7),流速1.0 m L/min,在紫外检测器波长为210 nm处进行测定。结果表明:在优化色谱条件下,6种有机酸在线性范围内相关性良好,相关系数R2≥0.999,各添加水平回收率在92.82%~102.12%之间,方法的精密度均小于5.0%,方法的检出限在0.1~0.7 mg/L范围。本方操作简单、准确,适合于分析苹果醋中有机酸的含量。      

Supercritical fluid and solid–liquid extraction of phenolic antioxidants from grape pomace: a comparative study

Distilled white grape pomace (Vitis vinifera var. Garnacha) was subjected to extraction by using two different methods: (1) solid–liquid extraction (SLE) employing 96% ethanol and water and (2) supercritical extraction (SFE) by running carbon dioxide coupled with ethanol as a modifier. Higher phenolic concentrations of extracts were attained by SFE (∼400 ppm), doubling those obtained by SLE. In the latter, increasing values of both temperature (from 25 to 50 °C) and contact time (from 30 to 90 min) and lower solvent-to-solid ratios (from 5:1 to 1:1) resulted in an enhancement of extraction efficiency. In SFE, the addition of the modifier (8%) was also found to favour the release of phenolic compounds. Antiradical activity values—evaluated by the ability to scavenge DPPH radicals—were, as general, also higher for SFE extracts, although maximum values reached at were similar (73% inhibition versus 68%). Chromatographic profiles confirmed the diverse nature of phenolic species occurring in extracts obtained from both extraction methods. Extracts from SLE contained more proanthocyanidins, whereas SFE ones contained basically gallic acid, catechin and epicatechin. Protection against oil oxidation assayed with two samples confirmed these results.     

Production of triacylglycerol and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by the toluene-degrading bacterium Rhodococcus aetherivorans IAR1

Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) produced by various bacteria has been intensively investigated as a promising biodegradable plastic, but required a supply of an expensive precursor as a secondary carbon source for its production. In a previous study, we identified a new bacterial strain, Rhodococcus aetherivorans IAR1, which synthesizes PHBV from toluene without the supply of a precursor. Toluene is the volatile organic compound most abundantly emitted to the environment. In the present paper, we show that R. aetherivorans IAR1 produces triacylglycerols (TAGs) simultaneously with PHBV. Both PHBV and TAGs were synthesized before the nitrogen source is completely exhausted. The cellular content of PHBV reached 10% of cell dry weight (CDW) and its synthesis ceased even during intermittent supply of toluene. However, accumulation of TAGs continued during cultivation and their cellular content reached 24% of CDW at the end of cultivation. Cerulenin inhibited TAG production and increased PHBV cellular content up to 30% of CDW. The mole fraction of 3-hydroxyvalerate (3HV) in PHBV produced from toluene increased from 60% to 80% during its accumulation. Fatty acid compositions of TAGs produced from acetate and toluene were different. At the end of cultivation, the mole fraction of C17:0, one of odd-carbon number fatty acids, was 5% on toluene or 10% on acetate while the mole fraction of 3HV in PHBV from toluene was as high as that in PHBV from acetate, suggesting that a C5 intermediate of toluene degradation might directly become a precursor of 3HV whereas propionyl-CoA is required for the incorporation of C17:0 into TAGs.     

Isolation of ursolic acid from apple peels by high speed counter-current chromatography

Cuticular waxes of four varieties of Malus domestica were investigated regarding their content of ursolic acid. Peels from Fuji, Gala, Smith and Granny Smith apples were extracted with chloroform, ethyl acetate and/or ethanol. The crude extracts were purified by high speed counter-current chromatography (HSCCC), by using mobile and stationary phases derived from the two-phase solvent system composed by n-hexane:ethyl acetate:methanol:water in the proportion of 10:5:2.5:1. The phase proportions and the relative distribution of ursolic acid between the two-phases were optimized by TLC and optical densitometry, by comparison with an authentic sample of ursolic acid. The amount of ursolic acid present in the extracts as well as the characterization of the isolated compound were made by high resolution gas chromatography coupled to mass spectrometry (GC–MS), ¹³C nuclear magnetic resonance (¹³C NMR), Infrared; and by comparing thin layer chromatography and flame ionization detection gas chromatography (GC–FID) patterns with the commercial sample. The average content of ursolic acid of 0.8 mg/cm² in the peel (around 50 mg per medium sized fruit with a surface area of 50–70 cm²) was found in the Fuji and Smith varieties, whereas 0.5 mg/cm² and 0.2 mg/cm² were the amounts calculated for Granny Smith and Gala, respectively. The HSCCC technique was shown to be a good method to purify free ursolic acid from apple peels and could represent a new technological tool to be developed to exploit industrially this source of product.     

同位素内标-高效液相色谱质谱法测定婴幼儿配方乳粉中维生素B6和生物素

目的建立同位素内标和高效液相色谱串联质谱法(highperformanceliquidchromatographytandem mass spectrometry, HPLC-MS/MS)同时测定婴幼儿配方乳粉中维生素B_6含量(吡哆醛、吡哆醇和吡哆胺)和B_7(生物素)的分析方法。方法样品加入同位素内标后,使用温水溶解,并用高氯酸沉淀蛋白质,上清液过滤后经HSS T3色谱柱分离,三重四极杆质谱仪检测,内标法定量。结果在最优化条件下,维生素B_6和生物素分别在1.0～100μg/L和0.10～10.0μg/L范围内线性关系良好,相关系数均大于0.998;定量限分别为10.0μg/100 g和1.0μg/100g。4种化合物的回收率为86.5%～97.9%,相对标准偏差为3.0%～6.6%。质控样品检测结果表明该方法准确可靠。结论该方法灵敏度高、净化效果好、定量准确,适用于婴幼儿配方乳粉中维生素B_6和维生素B_7的检测。     

Chemical composition,fatty acid content and antioxidant potential of meat from goats supplemented with Moringa (Moringa oleifera) leaves,sunflower cake and grass hay

The present study determined the chemical composition, fatty acid (FA) content and antioxidant capacity of meat from goats supplemented with Moringa oleifera leaves (MOL) or sunflower cake (SC) or grass hay (GH). The meat from goat supplemented with MOL had higher concentrations of total phenolic content (10.62 ± 0.27 mg tannic acid equivalent E/g). The MOL significantly scavenged 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic-acid (ABTS) radical to 93.51 ± 0.19% (93.51 ± 0.19%) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical to 58.95 ± 0.3% than other supplements. The antioxidative effect of MOL supplemented meat on catalase (CAT), reduced glutathione (GSH), superoxide dismutase (SOD) and lipid oxidation (LO) was significantly (P < 0.05) higher than other meat from goat feed on grass hay or those supplemented with sunflower seed cake. The present study indicated that the anti-oxidative potential of MOL may play a role in improving meat quality (chemical composition, colour and lipid stability).