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• Research on Using Endophytic Bacteria Isolated from Different Ecosystems

  Nguyen Hai Van, Nguyen Thi Minh

  Received: 03-05-2017 / Accepted: 14-06-2017

   Abstract PDF (VIETNAMESE)

  The aim of this study was to select and use the endophytic microorganism strains from different ecosystems for the production of multifunctional biofertilizer formulation for crop plants. The endophytic microorganisms were selected for their IAA and hydrolytic enzyme production, phosphorus solubilization, and antagonism to pathogenic microorganims. Six endophytic bacterial strains, 3TDG1, 3TDG4, 3TDG5, 3LC2, 3LDQ2 and 3CL2, with high bioactivity were selected from 32 endophytic bacteria strains. These strains were used for adding into the nutrient liquid obtained from treatment of livestock waste for the production of multifunctional biofertilizer formulation. These strains were 99% homologous with Klebsiella pneumoniae strain PSB1, Klebsiella oxytoca strain ALK033, Aeromonas caviae strain J5; Pseudomonas putida strain E1-4, Pantoea rodasii strain Y36 and Bacillus subtilis strain QB5413, respectively. The yield of Basella alba L. in tetsting experiment fertilized with multifunctional formulation increased by 89.51% as compared with the use of NPK fertilizer.

• Characterization of An Actinomycete Strain with Bioactivity against Vibrio parahaemolyticusCausing Disease on Shrimp

  Nguyen Xuan Canh, Ho Tu Cuong, Nguyen Thi Dinh, Pham Thi Hieu

  Received: 12-07-2016 / Accepted: 20-11-2016

   Abstract PDF (VIETNAMESE)

  An experiment was conducted to screen and identify the actinomycete trains that are capable of antagonizing Vibrio parahaemolyticuscausing disease on shrimp. Among of 96 isolated strains, three strains were obtained as capable of antagonizing Vibrio parahaemolyticusby agar diffusion plate method. The strain number 25.2 had strongest activity with a diameter of 15 mm clear zone of bacteria. The 25.2 strain showed white colonies but white colonies with grey borders after three and seven days of incubation, respectively. The strain did not produce soluble pigments on Gause-1 medium but grew well at temperatures between 30 - 45°C and neutral pH, and was tolerant to high salt concentration medium. The 25.2 strain was able to utilize several sources of carbon and nitrogen. Results of 16S rRNA sequence analysis showed that the strain 25.2 had a similarity of 96% compared with Streptomyces aureofaciens. Based on morphological characteristics, culture, physiological and biochemical characteristics and molecular biological analyses, the strain 25.2 was identified as Streptomyces aureofaciens.