Microbial Inoculation Increases Plant Absorbable Inorganic Nutrients in Rice-Derived Distillery Effluent

Abstract

To evaluate the effects of microbial inoculants to degrade organic plant nutrients and increase inorganic plant nutrients for bioconversion of distillery effluent, we inoculated and incubated 7 species (strains) of Aspergillus, 10 of Bacillus, 2 of Burkholderia, 3 of Mucor, 4 of Wickerhamomyces, and 9 of Pseudomonas at both the raw (3.9) and adjusted (7.0) pH levels in the rice-derived distillery effluent. The effluent inorganic nitrogen (N), which is the sum of nitrate (NO3−) and ammonium (NH4)–N, increased 6–12 fold after incubation with Aspergillus and Mucor species at the raw pH. Moreover, it increased 10–13 fold after incubation with Aspergillus and Bacillus at the adjusted pH. Increased inorganic N was predominantly present in the form of NH4. Interestingly, NO3–N increased 16–17 fold with Aspergillus, which was much higher than the increase in the NH4–N level. The phosphate (PO43−) content tended to increase upon inoculation with Burkholderia, and to decrease with Aspergillus and Mucor. These results indicated that the Aspergillus, Bacillus, Mucor, and Burkholderia genera contain species or strains that efficiently increase the levels of inorganic N and soluble phosphorus in rice-derived distillery effluent.