A total of twenty-five bacterial isolates obtained from mature compost to evaluate the solubilization potential of insoluble zinc oxide and zinc carbonate. An efficient zinc-solubilizing bacterial isolates (Zn14) were chosen. Thereafter, some of morphological and biochemical characteristics as well as 16S rRNA sequence indicated that the isolate belonging to Enterobacter cloacae. The effect of various carbon and nitrogen sources on the efficiency of Zn solubizilation were investigated under shaking and static conditions. It was found that the selected bacterial strain could solubilize Zn compounds under wide range of nutrient types.
Pot experiment was conducted at Sakha Agricultural Research Station, Sakha, Kafr El-Sheikh, Egypt to study the efficiency of using Enterobacter cloacae as Invivo Zn solubilizer either alone or along with amended zinc compounds (ZnO and ZnCO3) to the soil and its effect on growth parameters of Zea mays plants under sterile and non-sterile soil at the age of 30 and 60 days.
The results indicated that there is a highly significant response to increase Zn uptake in all treatments as compared to control. Also, the treatment with ZnO and E. cloacae was the more efficient in total chlorophyll, dry weight plant-1 and N, P and K percentages compared to control.
Hence, to solve zinc nutrition problem using a biofertilizer, it is obvious that E. cloacae is capable of solubilizing insoluble zinc compounds by inoculation to increase crop growth and saving soil fertility.