Agriculture Reference
In-Depth Information
autoclaving is the most commonly used and has the superiority among all employed
methods due to low cost and its ability to allow absolutely pure culture of inocula to
be prepared. For autoclaving, carrier material is packed in partially opened, thin-
walled polypropylene bags and autoclaved for 60 min at 121
C. However, during
autoclaving, some materials change their properties and produce toxic substances
which could be toxic to some bacterial strains. Once carrier is sterilized, it is ready
for mixing with PS inocula.
1.5.6.3 Mixing of Carrier with Inocula and Inoculant Packaging
The most suitable carrier material is first spread in clean, dry, sterile metallic or
plastic trays, and the bacterial culture developed at small scale (flasks) or large scale
(fermenter) is added to the sterilized carrier and mixed well manually by wearing
sterile gloves or mechanically by mixer. The culture suspension is added at a level
of 40-50 % WHC of the carrier. After proper mixing, the inoculant is kept in a
polythene bag (low density and thickness of the bag should be around 50-75
m) of
200 g capacity, sealed with electric sealer and allowed for curing for 2-3 days at
room temperature. Curing of carrier-based microphos can be done by spreading the
inoculant on a clean floor/polythene sheet by keeping in open shallow tubs/trays
with polythene covering for 2-3 days at room temperature before packaging. After
packaging, the packet containing microphos should legibly be marked with the
name of the manufacturer, name and cost of the product, batch number and strain
number, the mode of application, date of manufacture and expiry, full address of the
manufacturer and storage information. The microphos bags are now ready for
pot/field application or can be stored for later use. The microphos packets can,
however, be stored for about 3 months at 25
μ
2
C. Similarly, the two cultures of
the same groups or different groups [one or two fungi/AM fungi together or one
PSM and other PGPR] can be mixed together in order to produce a mixed/co-
inoculant. However, before the two organisms, identical or different, are used, their
compatibility towards each other and the persistence of P-solubilizing activity
under in vitro conditions must be ascertained (Khan et al.
2007
). If the two
organisms show any kind of antagonisms under laboratory conditions, they should
not be used together for developing a mixed or co-culture of the microphos.
Approaches used in the production and application of phosphate-solubilizing
microbes are shown in Fig.
1.3
.
1.5.6.4
Instruction for Microphos Storage
Carrier-based microphos packet should be stored in a cool place away from heat or
direct sunlight. The microphos packets may also be stored at room temperature or in
cold storage conditions. However, microphos should regularly (at least at 15 days
interval) be checked very carefully to evaluate the number of viable cells using
plate count method or serological methods (if available). The PSM density in
