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Azotobacter .pptx

This document summarizes information about the bacteria Azotobacter, including its classification, characteristics, isolation, mass production, and applications. Azotobacter is a genus of nitrogen-fixing soil bacteria that includes six known species. It is commonly isolated from soil using dilution plating techniques on nitrogen-free media. For use as an inoculant, it is mass produced through multiplication in flasks and fermenters, then mixed with a carrier and packaged. Azotobacter inoculants can be applied to fields through foliar spraying, seedling treatment, pouring slurries, or top dressing, and have been shown to increase crop yields for plants such as maize, sorghum, and rice by 6.7-

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AZOTOBACTER Classification, Characteristics-Isolation ,Mass Production and Field Applications
Classification  Kingdom - Bacteria  Phylum - Proteobacteria  Class - Gammaproteobacteria  Order - Pseudomonadales  Family - Pseudomonadaceae  Genus - Azotobacter
INTRODUCTION  This family includes various gram negative ,aerobic ,heterotrophic , catalase positive , free living diazotrophic bacteria .  The first species of the genus Azotobacter ,Azotobacter chroococcum was isolated from the soil In Holland in 1901 by Beijerinick.  Along with Rhizobium , Azotobacter is the most extensively studied genus among the saprophytes.  Winogradsky (1932) discovered that Azotobacter releases ammonia into the soil.
 At present six species of Azotobacter are known : 1. A.chroococcum 2. A.vinelandii 3. A.nigricans 4. A.paspali 5. A.armenicus 6. A.salinestris  Azotobacter chroococcum is the most commonly found species in soil.
CHARACTERISTICS  Gram negative , Rod shaped ,aerobic bacterium .  Pleomorphic ,ranging from rods to coccoid cells.  All the species of this genus forms cysts.  Motile by peritrichous flagella or non motile.  Production of water soluble and water insoluble pigments.  Nitrogen fixers , generally fix non-symbiotically atleast 10 mg of atmospheric nitrogen per gram of carbohydrates consumed.  The optimum environmental condition for Azotobactor are:temperature (25-30°C) ,high humidity ,aeration ,pH(7.2- 7.6),high salt concentration etc.
• Cyst of Azotobacter
ISOLATION OF AZOTOBACTER  The species of Azotobacter are isolated by soil dilution plate technique on nitrogen free medium(Jensen’s medium).  After 3 days incubation ,flat soft ,milky and mucoid colonies of Azotobacter grow on agar surface of the plates.  Besides ,it can also be isolated directly from soil by spreading a lump of soil on nitrogen free nutrient medium.  After incubation for 3 days colonies of Azotobacter grow on the surface of agar medium.
MASS PRODUCTION OF AZOTOBACTER INOCULANTS  Culture mass multiplied in two levels 1. At primary level in flasks using shaker. 2. Secondary stage multiplication in fermenter.  The steps involved are : 1. Culture selection and maintenance 2. Mass multiplication 3. Mixing of the Culture with carrier material and packing.
 After isolation ,the pure culture of Azotobacter is transferred to a flask containing sterile Jensen’s medium.  The flask is incubated on a rotary shaker or batch fermenter for a few days at 30°C.  The pure cells of Azotobacter developed in broth acts as starter culture which may be used for mass production of inoculate.  For 1L of starter culture,100L of medium is transferred to sterilized Jensen’s medium in a bioreactor with proper maintenance of temperature of 30°C and continously agitation for aeration.  Azotobactor multiples in medium.When inoculum density has reached to 10⁸ - 10⁹ cell/ml broth,it should be harvested so that carrier based inoculate should be prepared.
MIXING AND PACKAGING  Suitable carrier is dried and powered passing through a sieve.  Calcium Carobonate powder is added to neutralize the carrier followed by sterilization by autoclaving.  The harvested broth is poured over the carrier in such a way that 40% moisture is maintained.  The inoculants is mixed and curing is done for a week.  Then carrier based inoculants is packed in polythene bags so that it can be stored and sent in marker for sale.
APPLICATION Of Azotobacter INOCULANTS IN FIELDS  Azotobacter inoculants can be applied in different ways fir different types of plants in varying conditions: 1. FOLIAR APPLICATION:  Foliar application of Azotobacter biofertilizer individually or in combination with half of normal dose of chemical nitrogen fertilizer which increases leaf production in mulberry.  In this case foliar application is better than soil application.
 SEEDLING TREATMENT 1. This method is applicable for transplantation crop. 2. Roots of the seedlings to be transplanted are kept in slurry of carrier based inoculum for 10-30 minutes. 3. Then the seedlings are transplanted immediately. 4. A substantial amount of Azotobacter inoculants gets absorbed on the root surface of seedlings.
 POURING OF SLURRY: 1. Carrier based inoculants is diluted in water.Small amount of slurry is poured near the root zones. 2. Slurry may also be mixed with farmyard manure and administered near root zone.  TOP DRESSING: 1. Carrier based inoculants is diluted in water at 2kg Per hectare and mixed with farmyard manure at 20-25kg per hectare. 2. After transplantation of rice ,it is important to broadcast by dressing.
CROP RESPONSE AFTER FIELD APPLICATION  Field traits were conducted on different types of crop plants such as maize ,sorghum,cotton,vegetable crops,wheat ,rice etc.In different places by Indian Agricultural Research Institute (New Delhi).  Better responses of crop with A.chroococcum inoculants by 6.7-71% has been reported.  The beneficial effects of Azotobacter are due to Nitrogen fixation, synthesis of growth promoting substances and antifungal antibiotics.  A significant increases in dry matter of sorghum and maize with combined treatment of A.chroococcum + Azospirillum brasilense has been recorded.
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