Enumeration and characterization of nitrogen-fixing bacteria in an eelgrass (Zostera marina) bed

Four strains of marine nitrogen-fixing bacteria were isolated from the roots of eelgrass (Zostera marina) and from sediments in an eelgrass bed in Aburatsubo Inlet, Kanagawa Prefecture, Japan. Significant levels of nitrogenase activity were detected in all four strains after a few hours of incubation under anaerobic conditions. Nitrogenase activity in all cases was Na+ dependent. These strains grew anaerobically or under conditions of low oxygen, using molecular nitrogen as the sole nitrogen source. Bacterial growth in liquid nitrogen-free medium was accompanied by a marked pH decrease during the exponential growth phase. Neither yeast extract nor vitamins were required for the nitrogen fixation activity of these strains. Taxonomically, all strains were facultatively anaerobic, Gram-negative rods. They were motile in liquid medium by means of a single polar flagellum and required NaCl for their growth. These characteristics, as well as the guanine + cytosine content of their DNA (43.5 – 44.8 mol%), placed them in the family Vibrionaceae. These strains, however, could not be identified to the genus level because they were distinct from the two halophilic genera Vibrio and Photobacterium of the family Vibrionaceae by a variety of characteristics.

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Characterization of free nitrogen fixing bacteria of the genus Azotobacter in organic vegetable-grown Colombian soils

Brazilian Journal of Microbiology ◽

10.1590/s1517-83822011000300003 ◽

2011 ◽

Vol 42 (3) ◽

pp. 846-858 ◽

Cited By ~ 24

Author(s):

Diego Javier Jiménez ◽

José Salvador Montaña ◽

María Mercedes Martínez

Keyword(s):

Nitrogen Fixing ◽

Nitrogen Fixing Bacteria

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Isolation and characterization of salinity tolerant nitrogen fixing bacteria from Sesbania sesban (L) root nodules

Biocatalysis and Agricultural Biotechnology ◽

10.1016/j.bcab.2019.101325 ◽

2019 ◽

Vol 21 ◽

pp. 101325 ◽

Cited By ~ 1

Author(s):

N. Nohwar ◽

R.V. Khandare ◽

N.S. Desai

Keyword(s):

Root Nodules ◽

Sesbania Sesban ◽

Nitrogen Fixing ◽

Nitrogen Fixing Bacteria ◽

Isolation And Characterization

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Polyhydroxyalkanoate analysis inAzospirillum brasilense

Canadian Journal of Microbiology ◽

10.1139/m95-171 ◽

1995 ◽

Vol 41 (13) ◽

pp. 73-76 ◽

Cited By ~ 19

Author(s):

Robin Itzigsohn ◽

Oded Yarden ◽

Yaacov Okon

Keyword(s):

Azospirillum Brasilense ◽

Bacterial Species ◽

Carbon Sources ◽

Dry Mass ◽

Nitrogen Fixing ◽

Nitrogen Fixing Bacteria ◽

Qualitative And Quantitative ◽

Alkanoic Acids ◽

Quantitative Analyses

The considerable industrial interest in the qualitative and quantitative production of polyhydroxyalkanoates in microorganisms has led to the characterization of those synthesized in the nitrogen-fixing bacteria Azospirillum brasilense and Azotobacter paspali. In contrast to some other bacterial species, Azospirillum brasilense does not produce copolymers of hydroxyalkanoates when grown under the different carbon sources assayed, namely n-alkanoic acids, hydroxyalkanoates, and sugars with varying C:N ratios. Rather, only homopolymers of polyhydroxybutyrate were detected, comprising up to 70% of the cell dry mass. No copolymers were detected in Azotobacter paspali. Quantitative analyses of poly(β-hydroxybutyrate) are also presented.Key words: Azospirillum spp., Azotobacter paspali, polyhydroxyalkanoate analysis, PHA, PHB.

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