Dr Dubey  , a very intelligently placed question , my compliments to you . Infact , both nano-coating and encapsulation , both aid in extending the shelf life of microbes , their regulated release and their efficiency as well. I can cite an example of natural nano-coating through the formation interaction of humic acids/fulvic acids and their interaction with different soil microbial communities , especially the bacterial an d fungal communities. However , encapsulation is a kind of electrospining process and immobilisation of living biological material ( Salalha eta l. 2006 Nanotechnology 18: 4675-4681). 

infact , microbiology relates to nanoscience at a number of levels. Many bacterial entities are nano-machines in nature, including molecular motors like flagella and pili. Bacteria also form biofilms by the process of self-assembly (for example the formation of Curli-film by E. coli). The formation of aerial hyphae by bacteria and fungi is also directed by the controlled and ordered assembly of building blocks. Also, the formation of virus capsids is a classical process of molecular recognition and self-assembly at the nano-scale.

Silica is an excellent material for bioencapsulation because of its low cost, mechanicalrobustness, manufacturability, thermal and pH stability, and chemical inertness. However, fabrication of silica nanofibersvia traditional electrospinning methods requires organic solvents that may be toxic to the encapsulated bacteria.Continuous encapsulation of bacteria in water-insoluble, biocompatible, high-porosity nanofibrous membranes, as well as maintaining the activity of the encapsulated bacteria, are very important steps for scaling up production of bioreactive membranes to be used in industrial wastewater cleaning applications.

Hope , my response finds some utility in introducing the discussion further..

Dear Sir,

Thank you very much for your elaborated answer. It is useful to me. Further I wish to know that can I proceeds for the nano-encapsulation of PGPR with agro-waste nanofibers or not ?. Is It suitable for improving the shelf life and stress tolerance of the PGPR?

Dear Sir/Madam,

Kindly provide the relevant articles related to the nano-encapsulation of the PGPR/ PGPF.

Thanking you.

Rama Kant