Developing Beneficial Microbial Biofilms on Roots of Non legumes: A Novel Biofertilizing Technique

Abstract

Biofilms are often complex communities of multiple microbial species and remain attached to surfaces or with interfaces. Such beneficial biofilms can be developed in vitro and be used as biofertilizers (biofilmed biofertilizers , BBs) and biocontroling agents for nonlegumes , when applied at high cell densities. This chapter describes research studies conducted so far in this field with special attention into development of biofilms of N₂-fixing bacteria and P-solubilizing fungi. When these two distinct microbes were cocultured in vitro, the bacteria colonized fungal mycelia to form the biofilms. The biofilms showed higher rates of biological nitrogen fixation and organic acid production, which was directly proportional to the synthesis of indoleacetic acid-like substances , than microbes when used alone. The plant growth-promoting effects of such BBs were evaluated using rice (Oryza sativa), tea (Camellia sinensis), wheat (Triticum aestivum), and anthurium (Anthurium andraeanum). The biofilms formed nodule-like structures or “pseudonodules” on roots of such plants. For rice and tea, the results showed that recommended chemical fertilizers may be reduced by about 50% while applying BBs. Since this field of research is in its infancy, both laboratory and field experiments are required to fully explore the potential of this emerging biotechnological approach in the future.