Implementation and analysis of temperature control strategies for outdoor photobiological hydrogen production

For outdoor photobiological hydrogen production, the effective control of temperature in photobioreactors is a challenge. In this work, an internal cooling system for outdoor tubular photobioreactors was designed, built, and tested. The temperatures in the reactors with bacteria were consistently higher than those without bacteria, and were also strongly influenced by solar irradiation and ambient air temperature. The cooling protocol applied successfully kept the reactor temperatures below the threshold limit (38 °C) required for the bioprocess and provided a uniform distribution of temperature along the reactor tube length. The biomass growth and hydrogen production were similar in the reactors cooled co-currently and counter-currently. The biomass growth rate was 0.1 l/h, the maximum hydrogen production rate was 1.28 mol/m³/h, and the overall hydrogen yield obtained was 20 %. The change in the biomass was fitted using the logistic model while cumulative hydrogen production was fitted using the modified Gompertz equation.     

Dynamic modeling of temperature change in outdoor operated tubular photobioreactors

Bioprocess and Biosystems Engineering - In this study, a one-dimensional transient model was developed to analyze the temperature variation of tubular photobioreactors operated outdoors and the...     

Molecular beacon-equilibrium cyclization detection of DNA-protein complexes

Molecular beacon detection of equilibrium cyclization (MBEC) is a novel, high sensitivity technique that can allow DNA-protein complex formation to be studied under diverse conditions in a cost effective and rapid manner that can be adapted to high throughput screening. To demonstrate the ease and utility of applying MBEC to the investigation of the K(D) values of protein-DNA complexes, the sequence-specific Escherichia coli integration host factor (IHF) protein has been used as a test system. Competition between a labeled MBEC DNA construct and unlabeled duplex DNA for IHF binding allows the determination of K(D) values as a function of the DNA duplex sequence. This allows sequence specificity to be monitored while using only a single molecular beacon-labeled DNA. The robustness of MBEC for monitoring protein-DNA complex formation has been further demonstrated by determining the K(D) values as a function of salt concentration to investigate the net number of salt bridges formed in sequence-specific and -nonspecific IHF-DNA complexes. These MBEC results have been compared with those from other approaches.