Despite the numerous benefits of natural emulsifiers derived from microorganisms called bioemulsifiers, large-scale production using chemical culture medium is not cost-effective in terms of manufacturing process. Therefore, it can be possible to increase the production level of bioemulsifiers using inexpensive substrates and experimental designs. The aim of this study was to investigate the increase of bioemulsifier production by Lactobacillus plantarum su. plantarum PTCC 1896 (probiotic bacteria) and the culture medium of rice bran hydrolyzate extract. At this stage, the bioemulsifier produced by the bacterium was purified and identified. Then using Fourier transform infrared spectroscopy and gel permeation chromatography as well as determination of the chemical composition of the bioemulsifier, the functional group and the molecular structure, it was found that the bioemulsifier in this study was a combination of 86.2% polysaccharide and 14.7% of the protein with a high molecular weight of about 1.56×10 6 Dalton is soluble in water. In the next step, experimental designs were used to increase the production of bioemulsifier, in order to determine the effective factors first, the fractional factorial design using 5 independent factors of temperature, reducing sugar, agitation, tween 80 and yeast extract with Two levels were performed. The results of this study showed that the agitation factors and the interactions of Tween 80 and yeast extract had a significant effect (p 0.05) on biomolecular production. Then these three factors were evaluated for optimization at three levels by Response Surface Methodology (RSM) and Central Composite Design (CCD). In this method, the effect of each factor on the biomolecular production was investigated. The results of optimization showed that the amount of production yield predicted by the model did not differ significantly from the experimental value obtained from the practical test and the model set with p 0.0001 can be well used to increase bioemulsifier production yield used with the optimal amount. Finally, the optimum conditions for bioemulsifier production on the culture medium of hydrolyzed rice bran extract using Lactobacillus plantarum su. plantarum PTCC 1896 to achieve maximum production yield with concentration of 4 g/l yeast extract, 0.8 g/l tween 80 and amount 100 rpm agitating was achieved. The amount of bioemulsifier increased from 0.3 g/l before optimization to 0.69 g/l after the practical test and after optimization.Generally, the results of this study showed that increasing the yield of bioemulsifier production by Lactobacillus plantarum probiotic bacteria and low-cost waste reduces production costs in order to make production processes more economical and will lead food industries to use natural emulsifiers. Keywords: Bioemulsifier, Lactobacillus plantarum , Probiotic bacteria, Rice bran