Bioscience, Biotechnology, and Biochemistry
Online ISSN : 1347-6947
Print ISSN : 0916-8451
Volume 75 , Issue 12
Showing 1-30 articles out of 30 articles from the selected issue
Award Review
  • Masayuki OKUYAMA
    2011 Volume 75 Issue 12 Pages 2269-2277
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    A huge number of glycoside hydrolases are classified into the glycoside hydrolase family (GH family) based on their amino-acid sequence similarity. The glycoside hydrolases acting on α-glucosidic linkage are in GH family 4, 13, 15, 31, 63, 97, and 122. This review deals mainly with findings on GH family 31 and 97 enzymes. Research on two GH family 31 enzymes is described: clarification of the substrate recognition of Escherichia coli α-xylosidase, and glycosynthase derived from Schizosaccharomyces pombe α-glucosidase. GH family 97 is an aberrant GH family, containing inverting and retaining glycoside hydrolases. The inverting enzyme in GH family 97 displays significant similarity to retaining α-glycosidases, including GH family 97 retaining α-glycosidase, but the inverting enzyme has no catalytic nucleophile residue. It appears that a catalytic nucleophile has been eliminated during the molecular evolution in the same way as a man-made nucleophile mutant enzyme, which catalyzes the inverting reaction, as in glycosynthase and chemical rescue.
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Organic Chemistry Regular Paper
  • Wilanfranco C. TAYONE, Saki KANAMARU, Miho HONMA, Kazuaki TANAKA, Tats ...
    2011 Volume 75 Issue 12 Pages 2390-2393
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    Supplementary material
    A novel isochromanone, (S)-8-hydroxy-6-methoxy-4,5-dimethyl-3-methylene-isochromen-1-one (1), known 2 and previously reported metabolites from Leptosphaeria sp. KTC 727 (JCM 13076 = MAFF 239586) were isolated from the same source by culturing for a relatively long period. The results of the present study disclose their structures involving the absolute stereochemistry. The planar structures of these molecules were established by ESIMS and NMR spectral analyses. The absolute configuration of 1 was established by comparing its electronic circular dichroism (ECD) spectrum with that of structurally-related known compound 3. The relative stereochemistry of 2 was revealed by a combination of nuclear Overhauser effect (NOE) experiments and thermodynamic discussions. Successful transformation of 1 to 2 led us to assign the configuration of 2 after comparing their ECD spectra. These compounds exhibited weak antifungal activities against Cochliobolus miyabeanus.
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Organic Chemistry Note
Biochemistry & Molecular Biology Regular Papers
  • Yoshiya SETO, Shigeki HAMADA, Hiroyuki ITO, Chikara MASUTA, Hirokazu M ...
    2011 Volume 75 Issue 12 Pages 2316-2320
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    Recently we reported that rice salicylic acid (SA) glucosyltransferase (OsSGT) is active toward 12-hydroxyjasmonic acid (tuberonic acid, TA) and that OsSGT gene expression is induced by wounding stress. Here we report that tobacco SA glucosyltransferase (NtSGT), which is thought to be an ortholog of OsSGT, is also active toward TA. Although NtSGT expression is known to be induced by biotrophic stress, it was also induced by wounding stress in the same manner as OsSGT. These results indicate that this glucosyltransferase is important not only in biotrophic stress but also for wounding stress. It was found that this enzyme is dually functional, with activity both toward TA and SA.
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  • Sungwook CHAE, Mei Jing PIAO, Kyoung Ah KANG, Rui ZHANG, Ki Cheon KIM, ...
    2011 Volume 75 Issue 12 Pages 2321-2325
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    Oxidative stress is related to the synthesis of matrix metalloproteinases (MMPs), which cause skin aging. The protective effects of mangiferin derived from Anemarrhena asphodeloides were investigated against hydrogen peroxide (H2O2)-induced damage using human skin keratinocyte (HaCaT) cells. Mangiferin was found to scavenge intracellular reactive oxygen species (ROS), superoxide radicals, and hydroxyl radicals. ROS regulate MMPs gene expression and activation of proenzymes. Mangiferin inhibited H2O2-induced MMP-1 gene expression and protein levels as well as its activity. Moreover, it abrogated mitogen-activated protein kinase kinase (MEK)-extracellular signal-regulated kinase (ERK) pathway and stress-activated protein kinase/extracellular signal-regulated kinase (SEK)-c-JUN N-terminal kinase (JNK) pathway, which are induced by H2O2 treatment. And, it inhibited DNA binding activity of activator protein-1 (AP-1), a transcription factor of MMP-1 and downstream of ERK and JNK. Finally, it protected the human skin keratinocytes from H2O2-induced cell death. Taken together, these results indicate that mangiferin attenuated H2O2-induced MMP-1 activation via inhibition of ERK and JNK pathway and AP-1.
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  • Zhi-Yun DU, Yong-Fu JIANG, Zhi-Kai TANG, Rong-Qing MO, Gui-Hua XUE, Yu ...
    2011 Volume 75 Issue 12 Pages 2351-2358
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    A series of polyphenolic curcumin analogs were synthesized and their inhibitory effects on mushroom tyrosinase and the inhibition of 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical formation were evaluated. The results indictated that the analogs possessing m-diphenols and o-diphenols exhibited more potent inhibitory activity on tyrosinase than reference compound rojic acid, and that the analogs with o-diphenols exhibited more potent inhibitory activity of DPPH free-radical formation than reference compound vitamin C. The inhibition kinetics, analyzed by Lineweaver–Burk plots, revealed that compounds B2 and C2 bearing o-diphenols were non-competitive inhibitors, while compounds B11 and C11 bearing m-diphenols were competitive inhibitors. In particular, representative compounds C2 and B11 showed no side effects at a dose of 2,000 mg/kg in a preliminary evaluation of acute toxicity in mice. These results suggest that such polyphenolic curcumin analogs might serve as lead compounds for further design of new potential tyrosinase inhibitors.
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  • Chiho IKEBE, Manabu KONISHI, Dai HIRATA, Takahiro MATSUSAKA, Takashi T ...
    2011 Volume 75 Issue 12 Pages 2364-2370
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    Supplementary material
    We conducted a mitotic localization study on gene products encoded by 56 uncharacterized fission yeast ORFs that were transcriptionally up-regulated during meiotic division. Despite meiotic gene induction, these genes were expressed during mitosis as well. Seven gene products were localized in the nucleus and/or chromatin; another one was a mitosis-specific spindle pole body component and, intriguingly, its human homologue was also localized in the centrosome of cultured HeLa cells. Two products appeared to be localized in cytoplasmic microtubules, whereas four were mitochondrial proteins. Three other proteins were found in the medial ring upon cytokinesis and another was localized on the entire cell periphery. The remaining 38 proteins were detected in the cytoplasm and showed varied spatial patterns. This systematic study helps our integrated understanding of all the protein functions in the fission yeast as a eukaryotic model.
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  • Sheng-Kuo HSIEH, Jason T. C. TZEN, Tzong-Yuan WU, Ying-Ju CHEN, Wei-Hu ...
    2011 Volume 75 Issue 12 Pages 2371-2375
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    The maturation of mastoparan B, the major toxin peptide in the venom of Vespa basalis, requires enzymatic cleavage of its prosequence presumably via sequential liberation of dipeptides. The putative processing enzyme, dipeptidyl peptidase IV, was expressed as a glycosylated His-tag fusion protein (rDPP-IV) via the baculovirus expression system. rDPP-IV purified by one-step nickel-affinity chromatography was verified by Western blot and LC-MS/MS analysis. The kcat/Km of rDPP-IV was determined to be in the range of 10–500 mM−1·S−1 for five synthetic substrates. The optimal temperature and pH for rDPP-IV were determined to be 50 °C and pH 9. Enzymatic activity of rDPP-IV was significantly reduced by 80 and 60% in the presence of sitagliptin and phenylmethylsulfonyl fluoride respectively.
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  • Tami L. SIVY, Ray FALL, Todd N. ROSENSTIEL
    2011 Volume 75 Issue 12 Pages 2376-2383
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    The mevalonic acid (MVA) and methylerythritol phosphate (MEP) pathways for isoprenoid biosynthesis both culminate in the production of the two-five carbon prenyl diphosphates: dimethylallyl diphosphate (DMAPP) and isopentenyl diphosphate (IPP). These are the building blocks for higher isoprenoids, including many that have industrial and pharmaceutical applications. With growing interest in producing commercial isoprenoids through microbial engineering, reports have appeared of toxicity associated with the accumulation of prenyl diphosphates in Escherichia coli expressing a heterologous MVA pathway. Here we explored whether similar prenyl diphosphate toxicity, related to MEP pathway flux, could also be observed in the bacterium Bacillus subtilis. After genetic and metabolic manipulations of the endogenous MEP pathway in B. subtilis, measurements of cell growth, MEP pathway flux, and DMAPP contents suggested cytotoxicity related to prenyl diphosphate accumulation. These results have implications as to understanding the factors impacting isoprenoid biosynthesis in microbial systems.
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Biochemistry & Molecular Biology Notes
  • Ah-Young SHIN, Hwan-Sik KIM, Si-Seok LEE, Min-Gon KIM, Yun-Jeong HAN, ...
    2011 Volume 75 Issue 12 Pages 2411-2414
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    Phytochromes are photoreceptors that regulate many aspects of plant growth and development in response to red/far-red light signals from the environment. In this study, we analyzed chromophore ligation and photochromism of missense phytochrome mutants in the Per-Arnt-Sim (PAS)-related domain (PRD). Among the 14 mutants analyzed, the Gly768Asp mutant of Avena phytochrome A showed aberrant photochromism and dark reversion, suggesting that amino acid residues in the C-terminal domain affect the photochemical properties of the photosensory N-terminal domain.
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  • Tomoko MAEHARA, Tomoyuki TAKAI, Hiroaki ISHIHARA, Makoto YOSHIDA, Kiyo ...
    2011 Volume 75 Issue 12 Pages 2415-2417
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    The effect of lime pretreatment of brown midrib sorghums on enzymatic saccharification was investigated. Under most of the pretreatment conditions, the saccharification yields of bmrs were higher than those of the normal counterparts. This result suggests that bmr is useful to reduce pretreatment costs, because the amount of lime necessary for the pretreatment of biomass can reduced by using bmr mutants.
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  • Masataka KAJIKAWA, Takahiro FUJIBE, Shimpei URAGUCHI, Kyoko MIWA, Toru ...
    2011 Volume 75 Issue 12 Pages 2421-2423
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    Boron is an essential nutrient for plants, but it is toxic in excess. Transgenic rice plants expressing an Arabidopsis thaliana borate efflux transporter gene, AtBOR4, at a low level exhibited increased tolerance to excess boron. Those lines with high levels of expression exhibited reduced growth. These findings suggest a potential of the borate transporter BOR4 for the generation of high-boron tolerant rice.
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Food & Nutrition Science Regular Papers
  • Sayaka YOSHIOKA, Takao TERASHITA, Hajime YOSHIZUMI, Norifumi SHIRASAKA
    2011 Volume 75 Issue 12 Pages 2278-2282
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    Whisky exerts an inhibitory effect on melanogenesis in B16 cells, the anti-melanogenic activity being positively correlated with the aging period and anti-oxidative activity of whisky. We examined the correlation between the inhibition of melanogenesis and the concentration of each compound in various whiskies to evaluate the importance of 11 different whisky polyphenols, including ellagic acid, gallic acid and lyoniresinol, in the anti-melanogenic activity of whisky. The concentration of all the compounds was positively correlated with the anti-melanogenic activity of whisky. Ellagic acid, gallic acid and lyoniresinol were the predominant polyphenols in the whiskies measured by HPLC. These three compounds also significantly inhibited the melanogenesis and tyrosinase activity in B16 cells. Ellagic acid, gallic acid and lyoniresinol were confirmed as the major participants in the anti-melanogenic activity of whisky.
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  • Hiroya KAWASAKI, Atsuko YAMADA, Ryota FUSE, Tohru FUSHIKI
    2011 Volume 75 Issue 12 Pages 2288-2292
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    We investigated to determine whether dried bonito broth flavor induces a reinforcing effect using the conditioned place preference (CPP) test. Only dried bonito broth did not induce CPP. Sucrose induced CPP in 20% solution. A 21.86% dextrin solution, with the same calorie content as the 20% sucrose solution, did not induce CPP, but a dextrin solution flavored with dried bonito broth (BD) induced CPP. An AD solution containing the same concentrations of dextrin, NaCl, IMP, GMP, and amino acids as found in BD tended to increase the time spent in the conditioned box but did not significantly. Aromatic compounds, such as citral, vanillin, and menthol flavored AD solutions did not induce CPP, whereas an AD solution supplemented with dried bonito flavoring agent induced CPP. In mice with transected olfactory nerves, CPP was not induced by voluntary intake of BD. These results suggest that the aromatic profile of the dried bonito broth plays an important role in BD-induced CPP.
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  • Hiromitsu NAKANISHI, Shinji ONOSE, Eriko KITAHARA, Sukunya CHUMCHUEN, ...
    2011 Volume 75 Issue 12 Pages 2293-2296
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
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    Mulberry leaves have been used as the sole food for silkworms in sericulture, and also as a traditional medicine for diabetes prevention. Mulberry leaf components, for example 1-deoxynojirimycin (1-DNJ), inhibit the activity of α-glucosidase and prevent increased blood glucose levels, and they are highly toxic to caterpillars other than silkworms. The α-glucosidase inhibitory activity of mulberry leaves changes with the season, but it is unknown which environmental conditions influence the α-glucosidase inhibitory activity. We investigated in this study the relationship between the α-glucosidase inhibitory activity and environmental conditions of temperature and photoperiod. The results demonstrate that low temperatures induced decreasing α-glucosidase inhibitory activity, while the induction of newly grown shoots by the scission of branches induced increasing α-glucosidase inhibitory activity. These results suggest that the α-glucosidase inhibitory activity was related to the defense mechanism of mulberry plants against insect herbivores.
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  • Nao INOUE, Koji NAGAO, Saori NOMURA, Bungo SHIROUCHI, Masashi INAFUKU, ...
    2011 Volume 75 Issue 12 Pages 2304-2308
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    The effects of a hot water extract and fractional extracts from rabbiteye blueberry (Vaccinium ashei reade) leaves (BBL) on lipid metabolism were studied in obese Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Feeding the hot water extract and fractional extracts from BBL alleviated hepatic triglyceride accumulation in the rats. Additionally, feeding with the flavonol glycoside (FG) and proanthocyanidin (PA) fractions lowered serum cholesterol levels in the obese rats. The results from measurements of the hepatic enzyme activity indicate that the hypolipidemic effects of the hot water extract and the PA fraction might be attributable to enhanced lipolysis in the liver. The reduced serum levels of C-reactive protein, an inflammatory cytokine, by the chlorogenic acid + rutin fraction and FG fraction might be associated with alleviating the metabolic abnormalities in obese rats. These results indicate that the BBL extracts, and especially FG and PA, exerted hypolipidemic effects on obese OLETF rats and suggest that an infusion of BBL can be useful as a dietary hypolipidemic component.
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  • Yuji MATSUDA, Misato KOBAYASHI, Rie YAMAUCHI, Makoto OJIKA, Masanori H ...
    2011 Volume 75 Issue 12 Pages 2309-2315
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    We have previously demonstrated that coffee and caffeine ameliorated hyperglycemia in spontaneously diabetic KK-Ay mice. This present study evaluates the antidiabetic effects of coffee and caffeine on high-fat-diet-induced impaired glucose tolerance in C57BL/6J mice. C57BL/6J mice fed a high-fat diet were given regular drinking water (control group), or a 2.5-fold-diluted coffee or caffeine solution (200 mg/L) for 17 weeks. The ingestion of coffee or caffeine improved glucose tolerance, insulin sensitivity, and hyperinsulinemia when compared with mice in the control group. The adipose tissue mRNA levels of inflammatory adipocytokines (MCP-1 and IL-6) and the liver mRNA levels of genes related to fatty acid synthesis were lower in the coffee and caffeine groups than those in the control group. These results suggest that coffee and caffeine exerted an ameliorative effect on high-fat-diet-induced impaired glucose tolerance by improving insulin sensitivity. This effect might be attributable in part to the reduction of inflammatory adipocytokine expression.
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  • Yi-qun LIU, Ying LIU, Tatsuya MORITA, Kimio SUGIYAMA
    2011 Volume 75 Issue 12 Pages 2333-2339
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    The effects of dietary supplementation with 0.5% methionine, 2.5% serine, or both on hyperhomocysteinemia induced by deprivation of dietary choline or by dietary addition of 0.5% guanidinoacetic acid (GAA) were investigated in rats fed a 10% casein diet. Hyperhomocysteinemia induced by choline deprivation was not suppressed by methionine alone and was only partially suppressed by serine alone, whereas it was completely suppressed by a combination of methionine and serine, suggesting a synergistic effect of methionine and serine. Fatty liver was also completely prevented by the combination of methionine and serine. Compared with methionine alone, the combination of methionine and serine decreased hepatic S-adenosylhomocysteine and homocysteine concentrations and increased hepatic betaine and serine concentrations and betaine-homocysteine S-methyltransferase activity. GAA-induced hyperhomocysteinemia was partially suppressed by methionine alone, but no interacting effect of methionine and serine was detected. In contrast, GAA-induced fatty liver was completely prevented by the combination of methionine and serine. These results indicate that a combination of methionine and serine is effective in suppressing both hyperhomocysteinemia and fatty liver induced by choline deprivation, and that methionine alone is effective in suppressing GAA-induced hyperhomocysteinemia partially.
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  • Uracha RUNGSARDTHONG RUKTANONCHAI, Wanwisa SRINUANCHAI, Somsak SAESOO, ...
    2011 Volume 75 Issue 12 Pages 2340-2345
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    The complexation between two isomers of citral in lemongrass oil and varying types of cyclodextrins (CDs), α-CD, β-CD, and HP-β-CD, were studied by molecular modeling and physicochemical characterization. The results obtained revealed that the most favorable complex formation governing between citrals in lemongrass oil and CDs were found at a 1:2 mole ratio for all CDs. Complex formation between E-citral and CD was more favorable than between Z-citral and CD. The thermal stability of the inclusion complex was observed compared to the citral in the lemongrass oil. The release time course of citral from the inclusion complex was the diffusion control, and it correlated well with Avrami’s equation. The release rate constants of the E- and Z-citral inclusion complexes at 50 °C, 50% RH were observed at 1.32×10−2 h−1 and 1.43×10−2 h−1 respectively.
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  • Akihiro TAI, Takeshi SAWANO, Futoshi YAZAMA
    2011 Volume 75 Issue 12 Pages 2346-2350
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    We systematically evaluated the antioxidant activity of ethyl vanillin, a vanillin analog, as compared with the activities of vanillin and other vanillin analogs using multiple assay systems. Ethyl vanillin and vanillin exerted stronger antioxidant effects than did vanillyl alcohol or vanillic acid in the oxygen radical absorbance capacity (ORAC) assay, although the antioxidant activities of vanillyl alcohol and vanillic acid were clearly superior to those of ethyl vanillin and vanillin in the three model radical assays. The antioxidant activity of ethyl vanillin was much stronger than that of vanillin in the oxidative hemolysis inhibition assay, but was the same as that of vanillin in the ORAC assay. Oral administration of ethyl vanillin to mice increased the concentration of ethyl vanillic acid, and effectively raised antioxidant activity in the plasma as compared to the effect of vanillin. These data suggest that the antioxidant activity of ethyl vanillin might be more beneficial than has been thought in daily health practice.
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  • Tadateru HAMADA, Mariko KUDO, Masao SATO, Nao INOUE, Koji NAGAO, Katsu ...
    2011 Volume 75 Issue 12 Pages 2359-2363
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
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    The effects were compared of T0901317, a liver X receptor agonist, on deposition in the liver and serum and lymphatic absorption of plant sterols in stroke-prone spontaneously hypertensive rats (SHRSPs) having a missense mutation in Abcg5, which codes for ATP-binding cassette transporter (ABC) G5, with those in Wistar rats. Both strains were pair-fed for 7 d with a 0.5% plant sterol diet with or without 5 mg/kg of body weight of T0901317. The deposition of plant sterols in the liver and serum was higher in SHRSPs than in Wistar rats. A significant reduction of plant sterol deposition was observed in Wistar rats, but not in SHRSPs when T0901317 was given. Both strains were then fed for 7 d with a control diet with or without T0901317. The lymphatic absorption of plant sterols was reduced to almost half the normal level by the T0901317 treatment. However, no difference in absorption was apparent between SHRSPs and Wistar rats regardless of the T0901317 treatment. These results suggest that the plant sterol deposition in SHRSPs was not necessarily caused by the increased absorption of plant sterols.
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Food & Nutrition Science Notes
Microbiology & Fermentation Technology Regular Papers
  • Masaki J. FUJITA, Nobutada KIMURA, Atsushi SAKAI, Yoichi ICHIKAWA, Tom ...
    2011 Volume 75 Issue 12 Pages 2283-2287
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    Supplementary material
    A biosynthetic gene cluster of siderophore consisting of five open reading frames (ORFs) was cloned by functional screening of a metagenomic library constructed from tidal-flat sediment. Expression of the cloned biosynthetic genes in Escherichia coli led to the production of vibrioferrin, a siderophore originally reported for the marine bacterium Vibrio parahaemolyticus. To the best of our knowledge, this is the first example of heterologous production of a siderophore by biosynthetic genes cloned from a metagenomic library. The cloned cluster was one of the largest of the clusters obtained by functional screening. In this study, we demonstrated and extended the possibility of function-based metagenomic research.
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  • Thanaporn LAOTHANACHAREON, Parichart KHONZUE, Nakul RATTANAPHAN, Phung ...
    2011 Volume 75 Issue 12 Pages 2297-2303
    Published: November 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    Enzymatic modification of pulp is receiving increasing interest for energy reduction at the refining step of the paper-making process. In this study, the production of a multi-fiber modifying enzyme from Mamillisphaeria sp. BCC8893 was optimized in submerged fermentation using a response-surface methodology. Maximal production was obtained in a complex medium comprising wheat bran, soybean, and rice bran supplemented with yeast extract at pH 6.0 and a harvest time of 7 d, resulting in 9.2 IU/mL of carboxymethyl cellulase (CMCase), 14.9 IU/mL of filter paper activity (FPase), and 242.7 IU/mL of xylanase. Treatment of old corrugated container pulp at 0.2–0.3 IU of CMCase/g of pulp led to reductions in refining energy of 8.5–14.8%. The major physical properties were retained, including tensile and compression strength. Proteomic analysis showed that the enzyme was a complex composite of endo-glucanases, cellobiohydrolases, beta-1,4-xylanases, and beta-glucanases belonging to various glycosyl hydrolase families, suggestive of cooperative enzyme action in fiber modification, providing the basis for refining efficiency.
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  • Hideki SAWAI, Kyungsu NA, Nanami SASAKI, Takashi MIMITSUKA, Shin-ichi ...
    2011 Volume 75 Issue 12 Pages 2326-2332
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    This report describes the production of highly optically pure D-lactic acid by the continuous fermentation of Sporolactobacillus laevolacticus and S. inulinus, using a membrane-integrated fermentation (MFR) system. The optical purity of D-lactic acid produced by the continuous fermentation system was greater than that produced by batch fermentation; the maximum value for the optical purity of D-lactic acid reached 99.8% enantiomeric excess by continuous fermentation when S. leavolacticus was used. The volumetric productivity of the optically pure D-lactic acid was about 12 g/L/h, this being approximately 11-fold higher than that obtained by batch fermentation. An enzymatic analysis indicated that both S. laevolacticus and S. inulinus could convert L-lactic acid to D-lactic acid by isomerization after the late-log phase. These results provide evidence for an effective bio-process to produce D-lactic acid of greater optical purity than has conventionally been achieved to date.
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  • Minoru TAKEDA, Takahiro MURANUSHI, Sawako INAGAKI, Takuya NAKAO, Shige ...
    2011 Volume 75 Issue 12 Pages 2384-2389
    Published: December 23, 2011
    Released: December 23, 2011
    [Advance publication] Released: December 07, 2011
    JOURNALS FREE ACCESS
    Supplementary material
    Bacterial strain B-009, capable of using racemic 1,2-propanediol (PD), was identified as a rapid-growing member of the genus Mycobacterium. The strain is phylogenetically related to M. gilvum, but has slightly different physiological characteristics. An NAD+-dependent enantioselective alcohol dehydrogenase, which acts on R-PD, was purified from the strain. The enzyme was a homodimer of a peptide coded by a 1047-bp gene (mbd1). A highly conserved sequence for medium-chain dehydrogenase/reductases with a preference for secondary alcohols was found in the gene. Hydroxyacetone was produced from R-PD by an enzymatic reaction, indicating that position 2 of the substrate was oxidized. The enzyme activity was highest for (2R,3R)-2,3-butanediol (R,R-BD), enabling the enzyme to be identified as (2R,3R)-2,3-butanediol dehydrogenase (R,R-BD-DH). A homology search revealed M. gilvum, M. vanbaalenii, and M. semegmatis to have ORFs similar to mbd1, suggesting the widespread distribution of genes encoding R,R-BD-DH among mycobacterial strains.
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Microbiology & Fermentation Technology Notes
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