**7. Potential of PSM to develop as a commercial level biofertiliser**

The distinctive and unique ability of PSMs to solubilise organic and inorganic phosphates, leads to their developed as commercial level bio fertilisers [10, 12]. Biofertilisers are microbiologically active, eco-friendly, low-cost products applied to soil expecting soil health and growth promotion of plants [10, 15]. Biofertilisers can be replaced by 50% instead of chemical fertilisers without any reduction of the yield [15]. These phosphate bio fertilisers are not crop-specific and able to be used for any type of plant, expecting growth promotion, high yield and crop quality through optimum phosphate absorption [10]. *Azotobacter* inoculation and *Bacillus* inoculants have success stories with yield increments of sugarcane and wheat. Application of the combination of *Bacillus megaterium* and *Azotobacter chroococcum* as biofertiliser remark the yield increment by 10–20%. *Bacillus circulans, Bacillus megaterium, Bacillus subtilis*, and *Pseudomonas striata* reach the commercial level in the phosphate biofertiliser industry [10].

Biofilm inoculants and nano-bio inoculants are ultra-modern techniques in biofertiliser formulation technology. Biofilm inoculants are the combination of two microorganisms, while one microorganism colonises over the other microorganism. The second microorganism act as a biotic surface for the first microorganism to develop a metabolically enhanced biofilm rather than a single culture [3]. Even though these relationships affect the high phosphate solubilisation and growth promotion of plants, the abundance in the soil is very low [3, 79]. Therefore, applying these biofilms as biofertilisers through artificial formulation is advantageous in agriculture [3]. *Pleurotus ostreatus*, *Xanthoparmelia mexicana* and *Penicillium* spp. are the most prominent PSMs, which have the potential to be used in biofilms for substantial impact [80].
