Preparation of liquid bacteria fertilizer with phosphate-solubilizing bacteria cultured by food wastewater and the promotion on the soil fertility and plants biomass

Food waste treatment produced a large amount of food wastewater (FWW), containing a significant quantity of organic matter, which could benefit the growth of microorganisms. In this study, Kosakonia cowanii (T3) isolated from the wheat rhizosphere, was inoculated into the FWW to prepare phosphate-solubilizing bacteria (PSB) liquid fertilizer, and the effects of PSB fertilizer on soil fertility and Pakchoi growth were investigated. It was found that the concentration of soluble chemical oxygen demand (SCOD) and reducing sugar was reduced by 70.4% and 72.2% in the period of PSB culture. The PSB fertilizer increased the fresh weight, leaf length, and leaf width of Pakchoi by 62.10%, 36.74%, and 27.93%, respectively (P < 0.05), attributed to the escalation of available P concentration and catalase activity, which were closely related to plant growth. The biomass of Pakchoi and soil fertility were also enhanced by raising the activity of soil phosphatase and catalase. By analyzing the rhizosphere bacterial community after inoculating the fertilizer, it was found that the dominant phyla with relative abundance were Proteobacteria, Chloroflexi, and Cyanobacteria, which were positively asso-ciated with phosphatase, catalase, and the growth indices of Pakchoi. Among them, the most abundance increment of bacteria occurred in Proteobacteria (39.72%). The results would provide strong support for the preparation of PSB liquid fertilizer by FWW and the potential effects on soil fertility and plant growth.

Automated summary

This study investigated the effects of using phosphate-solubilizing bacteria (PSB) liquid fertilizer prepared from food wastewater (FWW) on soil fertility and Pakchoi growth. The results showed that the PSB fertilizer significantly improved the growth of Pakchoi and soil fertility by increasing the concentration of available phosphorus and catalase activity. The dominant bacterial phyla in the rhizosphere were positively associated with phosphatase, catalase, and the growth indices of Pakchoi.