The procedure involves isolation, mass culture production and preparation of inoculants along with inoculant quality control.The individual organism can be mass multiplied using specific media either as small scale or as large-scale commercial production procedure using fermenters.The desired growth of organisms is then mixed with carrier materials and sealed in culture packets.The entire procedure is carried out under aseptic condition to avoid contamination from other undesired organisms.The quality of inoculant is regularly checked prior to distribution of individual biofertilizer culture.

Steps in the mass multiplication of Bio fertilizers: a)Strain Selection ,maintenance of pure culture.b)Preparation of broth culture.c)Preparation of broth culture at commercial scale, inoculant quality control,d)Mixing broth culture with carrier (blending) and curing Packing. All steps to be undertaken under aseptic conditions.

Laboratory scale production: Preparation of the Inoculum (broth) culture:a)Dispense 100 ml aliquots of the specified broth into flasks, and plug with non-­absorbent cotton.b)Autoclave flasks at 121°C for 20 minutes.c)Transfer 5-6 days old desired pure culture of bacteria aseptically into the flasks with the help of inoculation needle.d)Incubate flasks at 30 + 2°C on rotary shaker for 2-6 days depending on the organism.

Preparation of broth culture:a)Submerged culture technique employed for growing bacteria on mass scale.b)Sterilize battery of conical flasks each containing 400 ml broth medium in an autoclave.c)Add 5 to 25 ml of inoculums culture of desired organism aseptically into each flask and incubate on rotary shaker at 30+ 1°C for 2-6 days.

Commercial scale production:For large-scale production, fermenter are used for growing bacteria. pH is adjusted to 6.5 - 7.0. Inoculum should be added @ 5%. Continuous aeration is done by forcing sterile air through sparger. Incubate culture till the bacterial population reaches 1000000000cells/ml, and added to carrier.Otherwise, the broth should be rejected

Standards:The organism count in final broth cultures shall not be less than 1000000000 cells / ml. Otherwise, the broth should be rejected

Carriers for Bacterial inoculants:Carrier is the medium in which organisms are allowed to multiply .Different carrier materials viz., peat lignite , compost, leaf manures, cellulose powder, charcoal powder, coconut shell powder, rice husk powder, press mud etc are extensively used carrier for inoculum preparation.

Preparation of carrier material:Carrier is sun-dried upto a moisture level of 5 %.The carrier is ground to pass through a 100-200 mesh sieves.Particles coarser than this cause 'balling up' when wetted and adhere poorly to the seed coat at the time of inoculation. The survival of rhizobia is also poor in coarser carrier materials.The carriers are mixed with calcium carbonate to neutralize pH(6.5-7.0).Carrier is mixed with 10 % water before sterilization.The pretreated carrier is filled up to 2/3 of the capacity of the containers (steel trays,2x1-0.5 x0.5feet).Carriers are sterilized at 121°C for 3-4 hrs.continuously or 1hr each for three successive days.

Mixing Broth With Carrier (blending) and Curing:Grow culture in fermenter till population reaches to 1000000000 cells/ml.Blend inoculum broth with the finely powdered and sterilized carrier.Add broth @ 1/3 of the water holding capacity of the carrier.Thoroughly mix the broth culture with sterilized carrier in trays aseptically.Keep blended carrier for 24 hrs for curing to ensure acclimatization of bacteria with the carrier.

Packaging and Storage: After curing, the inoculant is ready to be packed.Select 50-75 micron polythene bags (6 x 10 inches).Dispense 200 g of inoculant in each bag manually or with automatic dispenser.Seal the polythene bags leaving 2/3 vacant spaces.Pin bags on few places for aeration. Keep inoculants for a week at room temperature (25-30°C).Store in a cold room(4°C) and despatch.

Quality Standards:The inoculant shall be a carrier-based one.The inoculant shall contain 1000000000 viable cells within 15 days of manufacture and 100000000 viable cells within 15 days before expiry.When the inoculant is stored at 25-30°C the inoculant shall have a maximum expiry period of 6 months.The inoculant shall not have any contamination.The inoculant should be infective and effective when tested on crop.The carrier material shall be in powder form.The manufacturers shall control the quality of broth and maintain records.The inoculant be packed in 50-75 micron polyethylene packets.The inoculant shall be stored cool place preferably at 15°C - 30°C ± 2°C.

Each packet shall be marked with information like: product name, specific crop, manufacturer’s name, batch no, ISI mark, date of manufacture, date of expiry, net quantity and storage instructions .https://youtu.be/O1FfEbpaiHw