This study investigated the optimum bacterial concentration and calcium lactate content in mortars containing recycled concrete aggregate (RCA) as full replacement of natural fine aggregate (NFA) for the first time. For this purpose, bacterial mortars with cells concentration of 103, 105 and 107 cells/ml were prepared. Calcium lactate was used as the organic precursor at dosages of 1%, 3%, and 5% of cement weight. The mechanical, durability, crack healing, and microstructural characteristics of the bacterial mixes were examined and compared to those of the control mix. The results indicated that incorporating bacterial cells with concentration of 105 cells/ml treated with 1% calcium lactate led to the optimal mix. The 28-day compressive strength of the optimal mix increased by 21% over that of the control mix. The lowest water absorption was also recorded for this mix, which was about 7% lower than that of the control mix. The scanning electron microscopy (SEM) images of the optimal mix showed a dense and compact microstructure as a result of calcite precipitation, which filled the air voids and reduced the pore size. Increasing the calcium lactate content lowered the quality of the pore system due to overproduction of calcium carbonate (CaCO3) crystals. This was confirmed by the results of porosimetry test using mercury injection method where the sample prepared with 5% calcium lactate and bacterial concentration of 103 cells/ml showed 450% higher total porosity as compared to the control sample. On the other hand, crack healing analysis revealed that the maximum healing in surface cracks occurred at the maximum bacterial concentration and calcium lactate content.