Multifunctional food waste fertilizer having the capability of Fusarium-growth inhibition and phosphate solubility: A new horizon of food waste recycle using microorganisms

Organic waste, including food leftovers and trade refuse, has been explored for its use as a nutrient source through a multitude of techniques. Composting; the dominant method, is criticized due to exhaustion of nutrients used for simultaneous microbial growth. Drying of food waste to low moisture levels, besides keeping the nutrition intact, offers the potential of growing desirable phyto-beneficial-cum-functional microbes, which can have additional benefits. Consequently, isolation of fungus from soil was carried out followed by characterization for confrontation against Fusarium, phosphate solubilization and utilization of food waste material. The food waste material was collected from University of Yamanashi Restaurant and dried up to approximately 3.8% moisture using Hitachi Household Garbage Dryer & Processor (ECO-B25). A pot experiment, growing Lactuca sativa (lettuce) and Brassica rapa, in selected fungal isolate-inoculated food waste material was conducted comparing with that of chemical, and organic fertilizer besides uninoculated food waste material. Results showed that one strain UY2015_11 (identified as Aspergillus niger) significantly inhibited the growth of Fusarium besides solubilizing hardly available iron, and calcium-type phosphates. Similarly, in a 13-week incubation experiment, mineralization of nitrate nitrogen from the food waste and fungal strain UY2015_11-inoculated food waste, was 23.9% and 17.0%, respectively. Later pot experiment indicated that the strain UY2015_11-inoculated dried food waste material showed same vegetable growth as chemical and organic fertilizer (rapeseed oil cake). Concluding, Aspergillus niger strain UY2015_11 isolated from soil inhibited the growth of Fusarium and solubilized hardly phosphate. Moreover, the strain UY2015_11 inoculated low moisture-food waste material showed the same vegetable growth as chemical and organic fertilizer (rapeseed oil cake).