Multiple starters consisting of two Bacillus amyloliquefaciens strains (MJ1-4 and EMD17), Pichiafarinosa SY80, and Rhizopus oryzae were used for Doenjang making. Bacillus strains were selected based on their abilities to inhibit toxinogenic fungi and Bacillus cereus, fibrinolytic activity, and their ability to confer good flavor to Cheonggukjang. P. farinosa SY80 and R. oryzae, previously isolated from soy sauce, were selected because they were not inhibited by two bacilli. Doenjang was prepared by inoculation of multiple starters (A1 Doenjang). Control Doenjang was prepared by inoculation of B. subtilis KACC 16750 (Natto strain) and Aspergillus oryzae KCCM 60166 (A2 Doenjang). Another control (A3 Doenjang) was prepared by inoculation of microorganisms present in rice straw. Doenjang samples were fermented for 70 days at 20℃. pH of 3 samples decreased from the initial value of 6.4 to 5.8~6.0 and titratable acidity (TA) increased from 0.6 to 1.1~1.3. The amount of amino-type nitrogen increased during fermentation. There were slight differences in moisture, crude-protein, and crude-fat contents after 70 days. Contamination of fungi was observed only in A3 Doenjang and B. cereus was not detected from all 3 samples. A1 Doenjang showed the highest fibrinolytic activity and A2 Doenjang the second. These results indicate that Doenjang made with carefully selected starters was functionally improved and microbially more safe.

Sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is a serious pest of many economically important crops. The insect has developed resistance to chemical insecticides. Therefore, the development of microbial agent is necessary. Among the several entomopathogenic fungi, Lecanicillium lecanii Btab01 which has high insecticidal activity was carried out this experiments. To develop mass culture, we subcultured L. lecanii Btab01 on PDA, TSA, SDA+Y, RA and GSA media at 25℃ incubator to select the optimal solid culture medium. Hyphal growth was measured every 3 or 4 days. L. lecanii Btab01 grew fastest in RA, followed GSA, SDA+Y, PDA and TSA. L. lecanii Btab01 was cultured on PDB, TSB, SDB+Y, RB, GSB media at 25℃, 180rpm shaking incubator to select the optimal liquid medium. Spore germination was measured by spread plate method every 12 or 24 hours. Spore germination appeared 7.8×108 CFU/ml after 4 days in RB, followed GSB (5.5×108 CFU/ml), SDB+Y (2.7×108 CFU/ml), TSB (1.7×108 CFU/ml) and PDB (0.6×108 CFU/ml).