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Carolina A. Lima,José L. Lima Filho,Benício B. Neto,Attilio Converti,Maria G. Carneiro da Cunha,Ana L. F. Porto 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.3
A 2^4 full factorial design was used to identify the main effects and interactions of the initial medium pH, soybean flour concentration, temperature and orbital agitation speed on extracellular collagenase production by Penicillium aurantiogriseum URM4622. The most significant variables for collagenase production were soybean flour concentration and initial medium pH that had positive main effects, and temperature that had a negative one. Protein concentration in soybean flour revealed to be a significant factor for the production of a collagenase serine proteinase. The most favorable production conditions were found to be 0.75% soybean flour, pH 8.0, 200 rpm, and 28ºC, which led to a collagenase activity of 164 U. The enzyme showed an optimum activity at 37℃ and pH 9.0,was stable over wide ranges of pH and temperature (6.0 ~10.0 and 25 ~ 45℃, respectively) and was strongly inhibited by 10 mM phenylmethylsulphonylfluoride. The firstorder rate constants for collagenase inactivation in the crude extract, calculated from semi-log plots of the residual activity versus time, were used in Arrhenius and Eyring plots to estimate the main thermodynamic parameters of thermoinactivation (E^*_d = 107.4 kJ/mol and ΔH^*_d = 104.7kJ/mol). The enzyme is probably an extracellular neutral serine collagenase effective on azocoll, gelatin and collagen decomposition.
Mohammad Hadi Dehghani,Aliakbar Dehghan,Hossein Alidadi,Maryam Dolatabadi,Marjan Mehrabpour,Attilio Converti 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.6
The adsorption of methylene blue dye (MBD) from aqueous solutions was investigated using a new composite made up of shrimp waste chitosan and zeolite as adsorbent. Response surface methodology (RSM) was used to optimize the effects of process variables, such as contact time, pH, adsorbent dose and initial MBD concentration on dye removal. The results showed that optimum conditions for removal of MBD were adsorbent dose of 2.5 g/L and pH of 9.0, and initial MBD concentration of 43.75mg/L and contact time of 138.65 min. The initial concentration of dye had the greatest influence on MBD adsorption among other variables. The experimental data were well fitted by the pseudo-second order kinetic model, while the Freundlich isotherm model indicated a good ability for describing equilibrium data. According to this isotherm model, maximum adsorption capacity of the composite was 24.5mg/g. Desorption studies showed that the desorption process is favored at low pH under acidic conditions.
Renan Rodrigues de Oliveira Silva,Paulo Victor Cuesta Calvo,Christian Adrian Merfels,Mikael Vitor Rodrigues Lima,Harrson S. Santana,Attilio Converti,Mauri Sergio Alves Palma 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.116 No.-
Continuous flow synthesis in microreactors has been integrated into chemical-pharmaceutical industryin recent years as an alternative to the batch process due to its advantages, especially process intensification,which can reduce the time for a new drug to be placed on the market on a large scale. This workaimed to transpose the synthesis of Lobeglitazone, a drug employed in the treatment of diabetes mellitustype 2, from batch to flow process in a microreactor as well as to determine the reaction kinetics of eachstep. The synthesis was carried out in five-steps, being synthesized intermediates 4-chloro-6-(4-methoxyphenoxy)pyrimidine (I1), 2-{[6-(4-methoxyphenoxy)pyrimidin-4-yl]methylamino}ethanol (I2), 4-(2-{[6-(4-methoxyphenoxy)pyrimidin-4-yl]methylamino}ethoxy)benzaldehyde (I3), 5-[4-(2-{[6-(4-methoxyphenoxy)pyrimidin-4-yl]methylamino}ethoxy)benzylidene]thiazolidine-2,4-dione (I4) andLobeglitazone. Intermediates I1 and I4 were synthesized in flow, while I4 was synthesized either in a continuousflow multistep synthesis or in a one-pot batch process. The flow syntheses of I1, I2 and I4 showed28.0 %, 61.8 % and 32.0 % yields at 25, 160 and 120 C, respectively, while the yield of I3 in batch processwas 73.3 % at 60 C. In one-pot batch process and continuous flow multistep synthesis, I2 was obtainedwith 13 and 16 % yields, respectively. These preliminary results constitute a starting point for the synthesisof this drug in flow on an industrial scale, with the aim of improving reaction performance using thisnew technology.