Application of Box-Behnken Design for the Optimized Production of Lactic Acid by Newly Isolated Lactobacillus plantarum JX183220 Using Cassava (Manihot esculenta Crantz) Flour.

Aim: The present study aimed at optimization of Lactic acid production using new isolate, Lactobacillus plantarum JX183220 with cassava flour (Manihot esculenta Crantz) in semi-solid fermentation by Response Surface Methodology. Study Design: Box-Behnken design of Response Surface Methodology was used. Place: Department of Chemical Engineering and Biotechnology, ANITS, Visakhapatnam. Materials and Methods: Lactobacillus plantarum JX183220 isolated from goat milk was used for the production of Lactic acid using cassava flour (CF) in semi-solid fermentation. Different fermentation parameters such as incubation time, inoculum volume, pH, temperature, substrate concentration (cassava flour), and Calcium carbonate concentration were initially optimized in preliminary studies. The substrate concentration, temperature and pH were chosen as potential variables and further optimized using Box-Behnken design of Response Surface Methodology. A second order polynomial regression model was fitted and was found adequate with a high coefficient of determination, R2 (0.9913). Validation experiment was carried out at optimum conditions of the parameters as determined from the model. Results: The preliminary experiments revealed that maximum production of lactic acid by Lactobacillus plantarum JX183220 was observed on 4th day of incubation with 2% inoculum and 0.3% Calcium carbonate. Optimization using Box -Behnken design of RSM resulted in maximum Lactic acid production of 18.3679 g/100 g of cassava at optimum conditions of substrate concentration, 1.225%; Temperature, 36.39°C and pH 6.43. These results were confirmed by validation experiment. Conclusion: Optimum parameters for the direct conversion of cassava flour starch to Lactic acid by new isolate, Lactobacillus plantarum JX183220 were determined. Box Behnken design of RSM was found to be convenient tool with 15 runs for optimizing lactic acid production. The lactic acid production could be further enhanced by saccharification and fermentation in future studies.

Mammalian-type dosage compensation mechanism in an insect — Gryllotalpa fossor (Scudder) — Orthoptera.

In Gryllotalpa fossor (Orthoptera) (23, X0 male; 24, XX female) we have established the existence of random X chromosome inactivation for dosage compensation of X-linked genes. Both cytogenetical (DNA replication and transcription) and biochemical (X-linked glucose-6-phosphate dehydrogenase) studies have indicated that one of the two X chromosomes in the female soma (hepatic caeca) is late replicating and transcriptionally silent leaving the other X chromosome to remain active as in males thereby ensuring the production of almost the same amount of X-linked glucose-6-phosphate dehydrogenase in both sexes. Even in oogonia, one of the two X chromosomes continues to retain inactive. Only prior to their entry into meiosis the inactive X chromosome is reactivated. Accordingly, there is two-fold increase m the level of X-linked glucose-6-phosphate dehydrogenase in oocytes, From this it is implied that the restoration of X chromosome inactivation should occur some time during early embryogenesis. Thus, dosage compensation in Gryllotalpa seems to be analogous to that in mammals. Our work bears testimony to the ancient origin of this mechanism.