3.1. Growth Kinetic of strain:
The growth curve of strain in both of mediums is shown in Fig. 1 (Supplementary data). It was apparent that 2 hours after nucleation of culture, strain interred to logarithmic phase and continues for 10 h in MRS broth and 12 h in PPM medium. Sonication continued in logarithmic phase in 2 h intervals.
3.2. The effect of ultrasound on growth kinetic:
The growth curves plotted for the two condition (with and without sonication) (Fig. 1), growth kinetic parameters calculated and compared (table 2). It was apparent that logarithmic phase duration and growth rate of strain were increased by sonication.
3.3. The effect of ultrasound on lactic acid production:
The variance analysis results of effect about the independent variables on amount of lactic acid production in MRS broth and PPM are shown in table 3 and table 4. The model was highly significant …show more content…
Conclusion:
The present study indicated that low intensity ultrasound can improve fermentation of Lactobacillus casei subsp.casei ATTC 39392. The following conclusions were obtained from this study:
I. Low intensity ultrasound increased production of lactic acid, cell reproduction and substrate consumption by Lactobacillus casei subsp.casei ATTC 39392.
II. Low intensity ultrasound increased growth indexes such as specific growth rate and logarithmic phase duration.
III. Through response surface methodology the amplitude and duration of the waves and peptone amount were optimized over the lactic acid production. The substrate consumption, the optimum values of amplitude, duration of waves and peptone amount were found to be 40%, 30 s and 6 (g/l), respectively. The optimum values of amplitude, and duration of the waves and peptone amount for cell reproduction were found 60%, 15 s and 10 (g/l) respectively.
IV. Sonication at low intensity had no adverse effect on cell morphology.
V. Permeat and its products can be used in production of lactic acid and led to decreasing of production
The growth curve of strain in both of mediums is shown in Fig. 1 (Supplementary data). It was apparent that 2 hours after nucleation of culture, strain interred to logarithmic phase and continues for 10 h in MRS broth and 12 h in PPM medium. Sonication continued in logarithmic phase in 2 h intervals.
3.2. The effect of ultrasound on growth kinetic:
The growth curves plotted for the two condition (with and without sonication) (Fig. 1), growth kinetic parameters calculated and compared (table 2). It was apparent that logarithmic phase duration and growth rate of strain were increased by sonication.
3.3. The effect of ultrasound on lactic acid production:
The variance analysis results of effect about the independent variables on amount of lactic acid production in MRS broth and PPM are shown in table 3 and table 4. The model was highly significant …show more content…
Conclusion:
The present study indicated that low intensity ultrasound can improve fermentation of Lactobacillus casei subsp.casei ATTC 39392. The following conclusions were obtained from this study:
I. Low intensity ultrasound increased production of lactic acid, cell reproduction and substrate consumption by Lactobacillus casei subsp.casei ATTC 39392.
II. Low intensity ultrasound increased growth indexes such as specific growth rate and logarithmic phase duration.
III. Through response surface methodology the amplitude and duration of the waves and peptone amount were optimized over the lactic acid production. The substrate consumption, the optimum values of amplitude, duration of waves and peptone amount were found to be 40%, 30 s and 6 (g/l), respectively. The optimum values of amplitude, and duration of the waves and peptone amount for cell reproduction were found 60%, 15 s and 10 (g/l) respectively.
IV. Sonication at low intensity had no adverse effect on cell morphology.
V. Permeat and its products can be used in production of lactic acid and led to decreasing of production