Studies on gut microbiota have revealed surprisingly diverse effects on human immune system and the disturbances in composition of the commensal microorganisms have shown to increase the incidence of diseases. The microorganisms from these metabolites are helpful in the regulation in the host system. This present review focuses on the intricate mechanisms of immune modulation by probiotic microorganisms and the pathways. Gut microbiome is an important modulator of brain functions as well as behaviour. This review specifically deals with the analysis of microbiota of gut in autism spectrum disorders. They are a group of neurological illness which causes difficulty in social behaviour and communication.

Cholesterol oxidase is an important enzyme with great commercial value in many clinical and industrial processes, such as determination of cholesterol levels in food, serum and other clinical samples as well as its potential application, as a biocatalyst for bioconversion of sterol compounds and as an insecticide. A Preliminary comparative study of cholesterol oxidase enzyme production from Streptomyces sp. strain NHIA_CH5 using six different media containing cholesterol in submerged fermentation was investigated. An increase in the production was detected after two days in all of the studied media with a maximum production of 23.7 U/mL, noticed in medium containing soluble starch, glucose, peptone, beef extract, MgSO4.7H2O, and NaCl. A classical (one-variable-at-a-time) method revealed that the elimination of MgSO4.7H2O and NaCl favored cholesterol oxidase enzyme production. Statistical optimization of the other components was studied using the screening method Plackett-Burman design followed by the modeling method of the central composite design (CCD). The results showed that beef extract and glucose are the variables that significantly influenced and considered as the most important factors for cholesterol oxidase production. Experiments of CCD based on response surface methodology determine the optimum concentrations of these significant medium components and revealed maximum cholesterol oxidase enzyme production (50.5 U/mL) at beef extract 55 g/L and glucose 40 g/L which represented 2- fold higher titers than acquired from the non-optimized medium.

Regressional-desirability approach in Box-Behnken response surface design was employed in this study to examine and optimize the osmotic dehydration process of Benincasa hispida cubes by impregnating in salt solution as an osmotic agent. The effect of independent parameters such as, concentration of solution (1-5%), sample to solution ratio (1:5-1:15 g/ml), temperature of osmotic solution (30-50℃) and time of immersion (30-180 min) on the weight reduction (WR), solid gain (SG), water loss (WL), rehydration ratio (RR) and shrinkage (SH) were studied. Second order polynomial mathematical models were developed for the responses and all the independent process variables have considerable consequence on the responses. The optimal dehydration process condition was found by regressional-desirability method and were: osmotic solution concentration of 2.73%, sample to solution ratio of 1:14 g/ml, osmotic solution temperature of 50℃ and osmotic dehydration time of 179 minutes with the mass transfer and quality properties such as weight reduction of 24.59%, solid gain of 7.69%, water loss of 32.28%, rehydration ratio 11.43%, shrinkage 8.58% and overall acceptability 8.19. The optimized samples were subjected to convective drying in cabinet tray dryer at different drying air temperatures (40, 50 and 60℃). The results indicated that the osmotic pre-treatment of the samples using salt solution was better in terms of water removal and reduction in the processing time when combined with convective drying process. Also, the quality of the final product was found to be good for the osmo-convective dried product using salt solution.