Nitrogen fixation associated with development and localization of mixed populations of Cellulomonas species and Azospirillium brasilense grown on cellulose or wheat straw

Journal Article · Tue Apr 01 00:00:00 EST 1986 · Appl. Environ. Microbiol.; (United States)

OSTI ID:5295732

Halsall, D M; Goodchild, D J

Mixed cultures of Cellulomonas sp. and Azospirillum brasilense were grown with straw or cellulose as the carbon source under conditions favoring the fixation of atmospheric nitrogen. Rapid increases in cell numbers, up to 10/sup 9/ cells per g of substrate, were evident after 4 and 5 days of incubation at 30 degrees C for cellulose and straw, respectively. Nitrogen fixation (detected by acetylene reduction measured on parallel cultures) commenced after 2 and 4 days of incubation for straw and cellulose, respectively, and continued for the duration of the experiment. Pure cultures of Cellulomonas sp. showed an increase in cell numbers, but CO/sub 2/ production was low, and acetylene reduction was not detected on either cellulose or straw. Pure cultures of A. brasilense on cellulose showed an inital increase in cell numbers (10/sup 7/ cells per g of substrate) over 4 days, followed by a decline presumably caused by the exhaustion of available carbon substrate. On straw, A. brasilense increased to 10/sup 9/ cells per g of substrate over 5 days and then declined slowly; this growth was accompanied by acetylene reduction. Scanning electron micrographs of straw incubated with a mixture under the above conditions for 8 days showed cells of both species in close proximity to each other. Evidence was furnished that the close spatial relatioship of cells from the two species facilitated the mutally beneficial association between them and thus increased the efficiency with which the products of straw breakdown were used for nitrogen fixation. 17 references.

• Research Organization: Commonwealth Scientific and Industrial Research Organisation, Canberra, Australia
• OSTI ID: 5295732
• Journal Information: Appl. Environ. Microbiol.; (United States), Vol. 51:4
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
BACTERIA
GROWTH
CELLULOSE
BIODEGRADATION
STRAW
CARBON DIOXIDE
CELLULOLYTIC ACTIVITY
CULTURE MEDIA
INCUBATION
NITROGEN FIXATION
SUBSTRATES
CARBOHYDRATES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
DECOMPOSITION
ENZYME ACTIVITY
MICROORGANISMS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
POLYSACCHARIDES
SACCHARIDES
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