Study on Isolation, Characterization and Identification of Endophytic Bacteria in Maize (Zea mays L.) Cultivated on Acrisols of the Southeast of Vietnam | Chapter 6 | Innovations in Microbiology and Biotechnology Vol. 2

 The variety of endophytic bacteria in maize (Zea mays L.) grown on Acrisols in Southeast Vietnam was investigated. In this region, twenty-eight maize stem and root samples were gathered from five different locations (provinces/cities). Endophytic bacteria were isolated in two mediums (LGI and NFb) and 16S rRNA gene fragments were amplified from DNA using eubacterial universal primers (p515FPL and p13B). A total of 301 isolates were isolated, and all of them were capable of nitrogen fixation, phosphate solubilization, and IAA biosynthesis, but 30 isolates stood out, and they were recognised as maize endophytes and nifH gene owners. The genomes of 30 endophytic bacteria isolates were found to have a high degree of similarity to the GenBank reference strains (between 97 percent and 100 percent ). Six isolates belonged to Bacillus (20.00%), and 24 isolates belonged to Proteobacteria (80.00%), including two alpha-proteobacteria (7%), six beta-proteobacteria (20%), and sixteen gamma-proteobacteria (16 gamma-proteobacteria (16 gamma-proteobacteria (16 gamma-proteobacteria (16 gamma-p (53 percent ). Proteobacteria had the highest Theta values based on Pi value (nucleotide diversity), and Theta values (per sequence) from S of SNP for DNA polymorphism were computed for each group, with Proteobacteria having the highest values in comparison to two groups. Because of their usefulness and biosafety, three isolates, DTN1b (Azotobacter vinelandii), VTN2b (Bacillus subtilis), and VTN7 (Enterobacter cloacae), have been recommended as suitable microbial inoculants or biofertilizers for sustainable maize cultivation in low Acrisols in Vietnam.

Author(S) Details

Dang Thi Ngoc Thanh
Department of Natural Science Teacher Training, Sai Gon University, HCM City, Vietnam.

Cao Ngoc Diep
Department of Microbiology Biotechnology, Biotechnology R&D Institute, Can Tho University, Can Tho City, Vietnam.

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Study on the Diversity of Heterotrophic Nitrogen Removal Bacteria in Piggery Wastes in the Mekong Delta, Vietnam | Chapter 7 | Innovations in Microbiology and Biotechnology Vol. 2

 The next phase was heterotrophic nitrogen removal in Pangasius fish (TRA) ponds in the Mekong Delta, now that we had the beneficial bacteria for wastewater treatment. A total of 2318 heterotrophic nitrogen removal (HNR) bacteria were isolated from piggery wastes (after biogas container) and divided into four categories: heterotrophic ammonia-oxidizing bacteria (569 isolates), nitrite-oxidizing bacteria (580 isolates), nitrate-oxidizing bacteria (600 isolates), and heterotrophic nitrifying and denitrifying bacteria (600 isolates) (569 isolates). The 16S rRNA gene was PCR amplified and sequenced almost completely. The HNR bacterium sequences were found to have a high degree of similarity to the GenBank reference strains (between 97 percent and 99.8 percent ). The consistency of phylogenetic trees based on 16S rDNA sequences was high, with nodes supported by high bootstrap (500) values. These suspected HNR isolates were split into four groups: Arthrobacter, Corynebacterium, Rhodococcus (high G+C content gram-positive bacteria), Staphylococcus, Bacillus (low G+C content gram-positive bacteria), and Klebsiella (low G+C content gram-positive bacteria) (gram-negative bacteria). In comparison to the other two groups, heterotrophic ammonium-oxidizing bacteria had the highest Pi values and heterotrophic nitrifying-denitrifying bacteria had the lowest Pi values. Theta values (per sequence) from S of SNP for DNA polymorphism showed that heterotrophic nitrate-oxidizing bacteria had the highest theta values. Many isolates had nitrogen utilisation ability at high concentrations (800–1200 mM), and high G+C gram-positive bacteria strains occupied greater than low G+C gram-positive bacteria strains, according to the current investigation on HNR bacteria from piggery wastes.

Author(S) Details

Cao Ngoc Diep
Biotechnology R&D Institute, Can Tho University, Vietnam.

Pham Viet Cuong
Vietnam Academy Institute of Science and Technology, Ha Noi City, Vietnam.

Bui The Vinh
CanTho Dairy Factory, Vietnam.

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