Isolation of potassium solubilizing bacteria in soil and preparation of liquid bacteria fertilizer from food wastewater

The production of food wastewater generated during the food waste treatment processes was tremendous, and large amounts of water-soluble organic matter dissolved into the food wastewater, which originate serious problems of both environmental and economic loss. However, food wastewater is abundance in organic matters without toxic substances, which is conducive to the growth of microorganisms. This study investigated the application of food wastewater after the food waste hydrothermal treatment (HT) to prepare potassium solubilizing bacteria (KSB) fertilizer. Two highly efficient KSB, Escherichia vulneris (K1) and Bacillus cereus (K2), were isolated from farmland soil and inoculated into the food wastewater, the organic matter content of which could be significantly increased after HT. In addition, pH, SCOD, and reducing sugar have significant effects on the growth of KSB. The optimal culture scheme of K2 in food wastewater was pH 8, temperature 30 ℃, table rotational speed 160 rpm, and inoculation amount 1.5%. The available K concentration of soil increased by 28.41 mg/kg as inoculated K2 fertilizer, which increased the garlic plant height by 23.53% and significantly affected plant height, maximum leaf width, maximum leaf length, fresh weight, and dry weight (P