Biopreservative technologies of food: an alternative to chemical preservation and recent developments

Food Science and Biotechnology - Despite centuries of developing strategies to prevent food-associated illnesses, food safety remains a significant concern, even with multiple technological...     

Effect of light irradiation on esterification of oleic acid with ethanol catalyzed by immobilized Pseudomonas cepacia lipase

The present study demonstrates the effect of light irradiation on the esterification of oleic acid catalyzed by immobilized Pseudomonas cepacia lipase. The reaction rates of all the experiments under light irradiation were found to be higher than dark conditions. The kinetics of reactions supported the Ping‐Pong Bi‐Bi mechanism with dead end inhibition by both the alcohol and acid substrates. Moreover, circular dichroism (CD) spectroscopy was used to analyze the effect of light on lipase enzyme. The CD spectroscopic studies confirmed that the conformational changes in the secondary structure of the lipase enzyme increased the reaction rate of light‐illuminated experiments, which might have opened up the active sites of enzymes and thus, resulted in higher reaction rates compared to dark reactions. These results have successfully demonstrated that the light illumination positively influenced the rate of P. cepacia enzyme‐catalyzed esterification reactions.     

Correlation of power generation with time-course biofilm architecture using Klebsiella variicola in dual chamber microbial fuel cell

In the present work, the wild type Klebsiella variicola was investigated in double chamber microbial fuel cell (MFC) using palm oil mill effluent as substrate which achieved high power density (4.5 W/m³) and coulombic efficiency (63%) while maintaining the moderate chemical oxygen demand (COD) removal efficiency (58%). The effect of biofilm formation on power generation over time was also evaluated and found that an effective biofilm with the discrete distribution of single layer microorganisms can produce high power corresponding to low charge transfer resistance. The growth of biofilm in multilayers consisting of outnumbered dead cells in the vicinity of the electrode surface caused the polarization resistance and diffusion resistance resulting in a sharp drop in the current generation. The removal of multilayer biofilm from the anode surface positively influenced the cell performance which led to a rapid increase in current generation and thus revealed that effective biofilm predominated by live cells can be an emergent factor for achieving maximum performance in MFC.