The 13 fungi were isolated from five optical equipments collected in Bac Giang province, Viet Nam. These fungi were classified as Aspergillus and Penicillium. Based on classification by morphology and sequence of ITS1 - 5,8S - ITS2 regions, three fungi were identified including 13.1 - Aspergillus flavus; 19.1 - Aspergillus aculeatus and 17.2 - Aspergillus niger.

Gastropoda is a large class in coastal waters in Central Vietnam. The interaction between microorganisms and Gastropoda mainly consists of symbiotic and parasitic relationships. In this study, biodiversity of microbial communities on some species of Gastropoda is evaluated, thereby predicting their interaction. From 12 samples of Gastropoda including 3 species: Trochus maculatus , Cypraea eglantica , Chicoreus bruneus , 101 microorganism strains including 79 bacterial strains (78.2%), 18 yeast strains (17.8%) and 4 actinomycetes strains (4.0%) were isolated. There were 15 strains (including 8 yeast strains, 5 bacterial strains and 2 actinomycetes strains) selected to identify based on sequence analysis of the D1/D2 region (yeast) and 16S rRNA gene (bacteria and actinomycetes). Based on the identification results, it is possible to predict the nutritional relationship between microorganisms and species of Gastropoda.

Vacomycin, which is produced by Streptomyces orientalis, is an antibiotic used in clinical treatment against pathogens ressistant to many popular antibacterial agents. The mutant strain Streptomyces orientalis 4912-81-61 producing high yeild of vancomycin was obtained as the result of N-methyl-N-nitro-N nitrosoguanidine treament on the protoplasts of orginal strain S. orientalis 4912. In the present work, the mutant strain Streptomyces orientalis 4912-81-61 was studied with respect to the biological characteristics. Antibiotic production of this mutant strain was enhanced by 94,3% compared to the original strain. The antibiotic produced by this mutant strain was detemined as vancomycin with a anti-microbial spectrum, inhibiting tested strains of general Bacillus, Staphylococcus and Escherichia. This mutant strain grow at favourable conditions such as pH range of 6-8, temperature 28-30oC, in medium containing NaCl concentration not more than 6%. The strain S. orientalis 4912-81-61 express enzyme activites to degrade casein, gelatin and starch. The fermentation process producign cancomycin by the mutant strain S.orientalis 4912-81-61 should be performed more convennient as its abilities of enzyme productivity and utilization of different sugars.

This paper presents some biological features and lovastatin biosynthesis capability of strain A. terreus VNA 05. It is found that the strain is capable of lovastatin biosynthesis and develops well in pH from 5 to 7.5 and at temperature 28oC - 30oC. The train consumes some commonly used carbon sources (glucose, saccharose, glycerol, mannose, lactose) and nitrogen sources (yeast extract, soybean powder, corn extracted water, peptone). A. terrus VNA 05 also yields enzyme activities hydrolyzing starch, casein, gelatin, xelluloza, which are favorable conditions for selecting nutrients during lovastatin fermentation.

20 endophytic yeast strains are isolated from 41 samples of flower, young fruit, old fruit of bananas Musa sapientum L.. The strains are divided into 16 groups based on morphological characteristics. The number of the endophytic yeast having cellulase, protease and amylase activity is 16, 15 and 6 respectively. When the endophytic yeast strains are studied by fingerprinting, they belong to 15 groups with high reliability.