Soft rot in apple caused by Rhizopus oryzae was found for the first time in Korea. A detailed description of the specimen is given along with its internal transcribed spacer rDNA sequence. The fungus was identified as Rhizopus oryzae based on the mycological characteristics, molecular data, and pathogenicity testing.
DNA, Ribosomal ; Fungi ; Korea ; Oryza ; Rhizopus

Rhizopus oryzae is reported for the first time on Cucumis melo L. var. makuwa Makino. A detailed description of this Korean specimen is given, along with its rDNA internal transcribed spacer sequence. On the basis of mycological characteristics and molecular data, the fungus was identified as R. oryzae Went & Prinsen Geerligs.
Cucumis ; Cucumis melo ; DNA, Ribosomal ; Fungi ; Oryza ; Rhizopus

Soft rot on banana fruit caused by Rhizopus oryzae was identified for the first time in Korea. Colonies were white to light brown and formed numerous sporangiospores. Optimum temperature for mycelial growth was 30degrees C. Sporangia were globose and 30~200 microm. Sporangiophores were usually straight, 8~20 microm, and rhizoids usually in groups of 3~5. Columella were globose to sub-globose and 90~110 microm. Sporangiospores were sub-globose or oval and 4~10 microm. Based on its mycological characteristics, molecular analysis, and pathogenicity to host plants, this fungus was identified as Rhizopus oryzae Went & Prisen Geerligs. This is the first report of soft rot on banana caused by Rhizopus oryzae in Korea.
Fruit ; Fungi ; Humans ; Korea ; Light ; Musa ; Oryza ; Rhizopus ; Sporangia

In order to carry out the process of the repeated intermittent L-lactic acid fermentation by self-immobilized Rhizopus oryzae, we investigated the effect of medium compositions on the morphology of Rhizopus oryzae. In submerged culture, fungi can be grown as broths of freely suspended mycelia and pellets or clumps, the pellets can be immobilized by themselves. The optimum medium composition for the first patch of fermentation was: 120 g/L glucose, 3 g/L NH4NO3, 0.14 g/L KH2PO4, 0.16 g/L NaH2PO4 (the concentration ratio of K+ and Na+ was 1:1). After 72 h fermentation, the physical form of Rhizopus oryzae was mostly uniform pellet with the diameter of 1.0-2.0 mm, the concentration of L-lactic acid was 100.8 g/L, and the conversion rate of glucose was 84%. During 16 batches of repeated fermentation, the L-lactic acid level was above 60.0 g/L and the conversion rate of glucose was 75%. The fermentation time of every batch was 24 h.
Cells, Immobilized ; metabolism ; Culture Media ; Fermentation ; Lactic Acid ; biosynthesis ; Rhizopus ; growth & development ; metabolism

Repeated batch fermentation with Rhizopus arrhizus immobilized by polyurethane was optimized in details including the time to replace, the volume of the replaced medium and the optimal composition of the medium to replace. Immobilized cells showed stability for repeated use. Immobilized cells could be used for 9 batches, lasting 140h in flask and 6 batches in 5L fermenter when the substitute culture medium consisted of (%): soybean flour 3.0, earthnut oil 0.5 and the liquid was replaced by 40% . The time for fermentation was reduced largely and the lipase productivity was 3 - 6 times as high as that in batch fermentation.
Biotechnology ; methods ; Cells, Immobilized ; metabolism ; Fermentation ; Lipase ; biosynthesis ; Plant Oils ; Rhizopus ; enzymology ; Soybeans

Directed evolution strategy (error-prone PCR) was conducted to improve the activity of lipase from Rhizopus chinensis CCTCC M201021. Through two rounds of ep-PCR and pNPP top agar screening, two optimum mutant strains 1-11 and 2-28 were obtained with 2 and 4 fold of enzyme activity higher than that of parent strain, respectively. DNA sequencing of mutant lipase 2-28 revealed four amino acid substitutions: A129S, K161R, A230T, K322R. According to the simulated protein structure of Rhizopus chinensis lipase, A129S, K161R, A230T were located on the surface of the protein. A230T substitution improved the stability of the alpha-helix loop. K322R, near the catalytic center of lipase, located at a loop, formed a salt-bridge with a nearby aspartic acid (negative charged). Electrostatic force pulled the loop to the opposite direction of the substrate channel and made it easier for substrate to enter the lipase catalytic domain. Purified lipase was characterized and the result showed that Km of 2-28 lipase decreased by 10% compared with Km of the parent lipase, and Kcat was 2.75 fold improved than that of the original lipase.
Directed Molecular Evolution ; Lipase ; chemistry ; genetics ; Point Mutation ; Protein Engineering ; Rhizopus ; enzymology ; genetics

As a therapeutic agent in thrombosis the fibrinolytic enzymes are of interest and the search for a new enzyme continues. A novel fibrinolytic enzyme was produced from Rhizopus chinensis 120, which was screened from the starter for brewing rice wine in the South of China, by solid fermentation, and purified through ammonium sulfate precipitation, hydrophobic interaction, ionic exchange and gel filtration chromatographies. The purified enzyme hydrolyzed fibrin, it cleaved the alpha-, beta- and gamma-chains of fibrinogen simultaneously, and it also activated plasminogen to plasmin. The enzyme hydrolyzed N-Succinyl-Ala-Ala- Pro-Phe-pNA, and Km was 0.23 mmol/L and Kcat 16.36 s(-1). The optimal temperature of the enzyme for hydrolying fibrin was 45 degrees C, and the optimal pH range of 6.8 - 8.8. The isoelectric point of the enzyme estimated by isoelectric focusing electrophoresis was 8.5 +/- 0.1. The enzyme was a glycoprotein. EDTA, PCMB, PMSF inhibited the activety of the enzyme, and SBTI, Lys, TPCK, Aprotinine had none obvious inhibition, which suggested that the activity centre of the enzyme had hydrosulfuryl, metal and serine. The first 12 amino acids of the N-termimal sequence of the enzyme were NH2-Ser-Val-Ser-Glu-Ile-Gln-Leu-Met-His-Asn-Leu-Gly, and had none homology with that of other fibrinolytic enzyme from other microbes. The novel fibrinolytic enzyme from Rhizopus chinensis 12# has potential to become a therapeutic agent in thrombosis.
Enzyme Stability ; Fermentation ; Fibrinolysin ; metabolism ; Fibrinolysis ; Fibrinolytic Agents ; chemistry ; Humans ; Plasminogen ; metabolism ; Rhizopus ; enzymology

Mucormycosis is an opportunistic fungal infection frequently associated with diabetes mellitus or an immunocompromised status. Rhinocerebral mucormycosis, the most frequent form of mucormycosis, is characterized by facial pain, swelling, fever, blood-tinged rhinorrhea and shows a rapidly progressive course. Herein, we describe an immunocompromised and diabetic woman with rhinocerebral mucormycosis initially misdiagnosed as herpes zoster.
Diabetes Mellitus ; Facial Pain ; Female ; Fever ; Herpes Zoster* ; Humans ; Mucormycosis* ; Rhizopus

Mucormycosis occurs primarily in patients with severe underlying illness, especially leukemia, lymphoma, and uncontrolled diabetes mellitus. Cutaneous mucormycosis is somewhat less frequently associated with systemic illness than other forms of mucormycosis. It develops where a break in the integrity of the skin has occurred as a result of surgery, burn, or other forms of trauma. We report herein a case of primary cutaneous mucormycosis due to Rhizopus arrhizus in a 24-year-old healthy man without systemic illness, who developed recurrent, prograssively extending, weeping and tender swollen ulcerative patches at the artificial trauma site on the right side of his face since 9 years of age. It was successfully treated with amphotericin B ointment combined with oral itraconazole and ketoconazole.
Amphotericin B ; Burns ; Diabetes Mellitus ; Humans ; Itraconazole ; Ketoconazole ; Leukemia ; Lymphoma ; Mucormycosis ; Rhizopus ; Skin ; Ulcer ; Young Adult

The effect of cultivation conditions on the optical purity of L(+)-lactic acid produced by Rhizopus oryzae HZS6 was investigated. The isomeric composition of lactic acid was influenced by the supplementation of L(+)-lactic acid to fermentation medium. L(+)-isomer increased with the dosage, no D(-)-lactic acid was observed when the concentration of supplemented L(+)-lactic acid in matrix was > or = 1.5 g/L. However, the L(+)-lactic acid yield, biomass and glucose conversion rate decreased with the dosage. With the same method, the supplementation of L(+)-lactic to substrate had no influence on isomeric composition of lactic acid by Lactobacillus and Escherichia coli.
Culture Media ; chemistry ; Fermentation ; Lactic Acid ; biosynthesis ; chemistry ; Rhizopus ; growth & development ; metabolism ; Stereoisomerism