Catalytic Esterification of Medium-Chain Fatty Acids:Kinetic Investigations

Medium-chain fatty acids (MCFA) are straight-chain fatty acids with aliphatic tails of 6 - 12 carbons, which can form medium-chain triglycerides. They are found mostly in animal fats and in the tropical vegetable oils. Because of their wide applications in industry, there is a growing demand of esters of medium-chain fatty acids production. The aim of our work was investigations of the kinetics of the synthesis of esters of MCFA in the presence of dowex catalyst in wide range of process parameters. Hexanoic, octanoic and decanoic acids were esterified with n-octyl alcohol in the presence of sulfuric acid and commercial dowex W50X8 as catalysts in an experimental semi-periodic glass tank reactor with instantaneous and complete water removal. Because of complete removal of water from the reacting mixture, thus eliminating the reverse hydrolysis reaction, the esterification can be assumed as irreversible reaction. The temperature range was 393 - 423 K, the range of initial mole ratio of alcohol to acid was 3 - 10. The kinetic parameters are given. The reaction kinetics appeared to be of the first order with respect to the acid. The effect of temperature on the reaction rate follows the Arrhenius equation well.

A potent fish pathogenic bacterial killer Streptomyces sp.isolated from the soils of east coast region,South India

Objective:To investigate the potentiality of the marine actinobacteria isolated from marine soil against fish pathogenic bacteria.Methods:east coast region(ECR)of Tamilnadu,South India.Then they were used for the isolation of actinobacteria by using conventional serial dilution technique on starch casein agar medium.The antibacterial activities of the actinobacteria were screened primarily by using cross streak plate method against fish pathogenic bacteria namely Vibrio alginolyticus,Vibrio parahaemolyticus,Vibrio cholera,Aeromonas sp.and Pseudomonas sp.The antimicrobial efficacy of the selected isolates was carried out with various organic solvents,and finally the active compound was subjected to chromatographic techniques including TLC and GC-MS.Results:In the present study,a total of 33 soil samples were collected from the Bay of Bengal,against fish pathogenic bacteria.Out of 21 antibacterial isolates,the isolate ECR77 was selected for further study based on its potential activity against fish pathogenic bacteria.Of the various solvents tested,the ethyl acetate extract had good antibacterial activity against the tested bacterial pathogens.The isolate ECR77 grew well on oat meal agar medium with 2%salt level at 35°C.GC-MS study found that the presence of bioactive compounds namely tetradecanoic acid,n-hexadecanoic acid and octadecanoic acid.The morphological,physiological,biochemical and cultural characteristics of the potential isolate were supported the identity up to generic level asStreptomyces sp.ECR77.Conclusions:The results obtained from this study concludes that the ECR soils of South India is a hot spot of novel bioactive compound producing marine actinobacteria with great pharmaceutical values.Of the 82 actinobacteria isolated,21(26%)isolates were possessed antibacterial activity.