Naoto Hirose

Okinawa Prefectural Fisheries and Ocean Research Center, Okinawa, Okinawa, Japan

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Publications (8)7.78 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Forty-three fungal producers for glycolipid biosurfactants, mannosylerythritol lipids (MELs), were isolated from leaves and smuts of sugarcane plants. These isolates produced MELs with sugarcane juice as nutrient source. The strains were taxonomically categorized into the genera Pseudozyma and Ustilago on the basis of partial sequences of the ribosomal RNA gene.
    Bioscience Biotechnology and Biochemistry 09/2012; 76(9):1788-91. · 1.27 Impact Factor
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    ABSTRACT: Sugarcane (Saccharum officinarum L.) wax that contains policosanol (a mixture of long-chain alcohols), is widely known to have beneficial effects on human health. In order to investigate differences in the composition and content of sugarcane wax in different sugarcane cultivars, the wax, policosanol, and long-chain aldehyde composition of eight sugarcane cultivars were examined. The wax composition of sugarcane was analyzed using HPLC coupled with an evaporative light scattering detector (ELSD). Sugarcane waxes were comprised of 55–60% aldehyde and sterol esters, 32–40% alcohol, and small amounts of TAG, acid, and plant sterols. Additionally, the composition of policosanol and long-chain aldehydes was determined using GC-FID and their mass fragment compounds were identified using GC-MS. The highest content of policosanol and long-chain aldehyde compounds (500 mg and 600 mg/100 g rind, respectively), was found in the hand-peeled rind of the Ni 22 sugarcane cultivar. The content of these compounds increased up to 72% during sugarcane maturation from October to January. This study indicated that the composition and content of wax, policosanol, and long-chain aldehydes may vary depending on the cultivar of the sugarcane and the specific part of the sugarcane analyzed, as well as on the degree of sugarcane maturity.Practical applications: Different sugarcane cultivars have been evaluated in terms of their usefulness as a source of policosanol, which is a valuable wax component that may have beneficial effects on human health. Policosanol is the common name that refers to a group of long-chain (C20–C30) aliphatic primary alcohols that are of great interest since their effects include reduction of platelet aggregation, reduction of low-density lipoprotein levels in blood, inhibition of cholesterol synthesis, and prevention of atherosclerosis development, and which also display ergogenic properties. The present study detailed the wax composition, including that of policosanol and long-chain aldehydes, of sugarcanes of different cultivars. The results of this study could provide a basis for selection of sugarcane cultivars in agricultural areas for wax or policosanol production.
    European Journal of Lipid Science and Technology 05/2012; 114(5). · 2.27 Impact Factor
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    ABSTRACT: Mannosylerythritol lipids (MELs) are glycolipid biosurfactants excreted by fungal strains. They show not only excellent surface-active properties but also versatile biochemical actions. Ustilago scitaminea NBRC 32730 has been reported mainly to produce a mono-acetylated and di-acylated MEL, MEL-B, from sucrose as sole carbon source. In order to make biosurfactant production more efficient, we focused our attention on the use of sugarcane juice, one of the most economical resources. The fungal strain produced MEL-B at the yield of 12.7 g/L from only sugarcane juice containing 22.4% w/w sugars. Supplementation with organic (yeast extract, peptone, and urea) and inorganic (sodium nitrate and ammonium nitrate) nitrogen sources markedly enhanced the production yield. Of the nitrogen sources, urea gave the best yield. Under optimum conditions, the strain produced 25.1 g/L of MEL-B from the juice (19.3% sugars) supplemented with 1 g/L of urea in a jar fermenter at 25 °C over 7 d. The critical micelle concentration (CMC) and the surface-tension at the CMC for the present MEL-B were 3.7×10(-6) M and 25.2 mN/m respectively. On water-penetration scan, the biosurfactant efficiently formed the lamella phase (L(α)) and myelins over a wide range of concentrations, indicating excellent surface-active and self-assembling properties. More significantly, the biosurfactant showed a ceramide-like skin-care property in a three-dimensional cultured human skin model. Thus, sugarcane juice is likely to be effective in glycolipid production by U. scitaminea NBRC 32730, and should facilitate the application of MELs.
    Bioscience Biotechnology and Biochemistry 07/2011; 75(7):1371-6. · 1.27 Impact Factor
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    ABSTRACT: An ustilaginomycetous anamorphic yeast species isolated from the leaves of Saccharum officinarum (sugarcane) in Okinawa, Japan, was identified as a novel Pseudozyma species based on morphological and physiological aspects and molecular taxonomic analysis using the D1/D2 domains of the large subunit (26S) rRNA gene and the internal transcribed spacer 1 (ITS1)-5.8S-ITS2 regions. The name Pseudozyma churashimaensis sp. nov. was proposed for the novel species, with JCM 16988(T) as the type strain. Interestingly, P. churashimaensis was found to produce glycolipid biosurfactants, a mixture of mannosylerythritol lipids (MELs), including a novel tri-acetylated derivative (MEL-A2), from glucose. The observed critical micelle concentration (CMC) and the surface tension at CMC of MEL-A2 were 1.7 × 10⁻⁶ M and 29.2 mN/m, respectively. Moreover, on a water-penetration scan, MEL-A2 efficiently formed different lyotropic liquid crystalline phases, including the lamella phase at a wide range of concentrations, indicating its excellent surface-active and self-assembling properties. The novel strain of the genus Pseudozyma should thus facilitate the application of glycolipid biosurfactants in combination with other MEL producers.
    Journal of Bioscience and Bioengineering 05/2011; 112(2):137-44. · 1.74 Impact Factor
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    ABSTRACT: Biosurfactants (BS) are produced by a variety of microorganisms from renewable resources, and have unique properties compared to chemical surfactants. In order to attain efficient production of BS from low-cost materials, we focused our attention on the use of sugarcane molasses. Fifteen yeast strains that are known as BS producers were examined for BS productivity from a culture medium consisting of only molasses and water. Among the strains tested, only Starmerella bombicola NBRC 10243 produced sophorolipids (SL), which are glycolipid BS. The culture conditions for the yeast were then investigated in a shake-flask culture. SL production was significantly affected by the pH of the medium and was highly accelerated at pH 6. Under the optimum conditions, the amount of SL reached 14.4 g/L after 120 h from a medium containing 150 g/L of total sugars. We tried to improve the production of SL further by feeding the molasses using a jar fermentor. Interestingly, the amount of SL increased up to 22.8 g/L after 120 h; the production rate was 1.6-fold higher than that in the shake-flask culture. These results suggest that the present yeast should have great potential for the low-cost production of SL, and facilitate the application of BS in various fields.
    Journal of oleo science 01/2011; 60(5):267-73. · 1.24 Impact Factor
  • Journal of The Japanese Society for Food Science and Technology-nippon Shokuhin Kagaku Kogaku Kaishi - J JPN SOC FOOD SCI TECHNOL. 01/2009; 56(6):343-349.
  • Journal of The Japanese Society for Food Science and Technology-nippon Shokuhin Kagaku Kogaku Kaishi - J JPN SOC FOOD SCI TECHNOL. 01/2008; 55(5):209-214.
  • Journal of The Japanese Society for Food Science and Technology-nippon Shokuhin Kagaku Kogaku Kaishi - J JPN SOC FOOD SCI TECHNOL. 01/2006; 53(12):627-633.

Publication Stats

13 Citations
7.78 Total Impact Points


  • 2011–2012
    • Okinawa Prefectural Fisheries and Ocean Research Center
      Okinawa, Okinawa, Japan
    • National Institute of Advanced Industrial Science and Technology
      • Research Institute for Innovation in Sustainable Chemistry
      Ibaraki, Osaka-fu, Japan