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Chromones group of compounds and their derivatives form the essential component of pharmacophores in many biologically active molecules. They exhibit a wide range of biological activities such as antibiotic, antitumor, antiviral, antioxidant, antipsychotic, and antihypoxic activities. These applications have stimulated a continuous search for the synthesis of new compounds in this field and are being extensively investigated. The various methodologies so far reported for the synthesis of these compounds with the compounds biological applications are discussed in this communication

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In the present study, Rhodobacter sphaeroides isolated from sewage water was investigated for photoproduction of hydrogen under different cultural conditions. The variation was done in carbon and nitrogen sources along with growth factors. It was found that lactose promoted more amounts of hydrogen production under anaerobic light conditions followed by mannitol, galactose, and sucrose respectively. Uracil was observed as a better nitrogen source as compared to histidine and thiourea. After screening most appropriate carbon source, nitrogen source and growth factor by the classical approach, statistical optimization technique opted for the enhancement of hydrogen production. The response surface methodology adopted in the present work is an efficient tool for strategic experimental design for optimizing process parameters of a multivariable process. Firstly, experiments were performed according to Box-Behnken design. The model predicted is quadratic with a high value of R 2 i.e. 0.9681 and maximum production recorded was 6.8 ml/30 ml. Thereafter, Central composite design based experiments were performed and 7.6 ml/30 ml production was achieved with an R 2 value of 0.8848 fitted inthe quadratic model. The work presented here suggests a green approach of enhanced hydrogen production to meet the future demand of clean fuel.

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Background and Objective: This study utilizes Rhodobacter sphaeroides bacteria for the photoproduction of hydrogen under various cultural conditions. R. sphaeroides was isolated from sewage water. We have examined different carbon and nitrogen sources for hydrogen production and further established the conditions for optimum hydrogen production by R. sphaeroides. Methods: The cumulative hydrogen produced by the bacteria at various intervals of time was measured using a Gas Chromatograph. Initially, by classical one factor at a time method, it was found that Benzoate and Glycine promote higher amounts of hydrogen production under anaerobic light conditions after 96 h. Results: The production was also observed to be enhanced in the presence of growth factors B12. Further, the Response Surface Methodology (RSM) was employed to optimize the hydrogen production. The first level of optimization was done using Box-Behnken Design (BBD) followed by Central Composite Design (CCD) method. The maximum production of hydrogen achieved by BBD and CCD was 6.8 ml/30 ml and 8.12 ml/30 ml, respectively. The significant model predicted is a quadratic model with R2 value 0.9459. Conclusion: Moreover, work presented here suggests an environment-friendly approach of harvesting H2, which could meet energy demand as clean fuel via the green route.