| Autor: |
Dos Santos JBC; Programa de Pós-Graduação em Engenharia Química, Universidade Federal de São Carlos, Rod. Washington Luiz, km 235, São Carlos, SP, 13565-905, Brazil., da Silva Cruz RG; Departamento de Engenharia Química, Universidade Federal de São Carlos, Rod. Washington Luiz, km 235, São Carlos, SP, 13565-905, Brazil., Tardioli PW; Programa de Pós-Graduação em Engenharia Química, Universidade Federal de São Carlos, Rod. Washington Luiz, km 235, São Carlos, SP, 13565-905, Brazil. pwtardioli@ufscar.br.; Departamento de Engenharia Química, Universidade Federal de São Carlos, Rod. Washington Luiz, km 235, São Carlos, SP, 13565-905, Brazil. pwtardioli@ufscar.br. |
| Abstrakt: |
This work evaluated a wild-type Streptomyces clavuligerus strain as a whole-cell lipase (Sc-WCL) producer by submerged fermentation. In an orbital shaker, lipase hydrolytic activity of 3000 U L -1 , measured at pH 9.0 and 37 °C by using p-nitrophenyl palmitate as substrate, was achieved after 36 h fermentation using glycerol-free production medium in a baffled Erlenmeyer flask at 28 °C and pH 6.8. Maximum productivity of 52.5 U L -1 h -1 was achieved after 24 h in bioreactor using glycerol-free production medium at pH 6.8 and 28 °C, with agitation at 400 rpm and aeration at 1 vvm. Sc-WCL was shown to be more active at 60 °C and pH 10.7, while higher activity retention was observed at 30-40 °C after 1 h incubation at pH 10. Sc-WCL showed to have potential to be used as biocatalyst in hydrolysis and esterification reactions. In the hydrolysis of p-nitrophenyl palmitate, lyophilized Sc-WCL expressed a hydrolytic activity (330 units g -1 solid, measured at 37 °C and pH 9.0) around 100-fold higher than the ones declared by a supplier of lyophilized powders of mixtures of intracellular lipases from Thermus thermophiles and Thermus flavus (≥3.0 units g -1 solid, measured at 65 °C and pH 8.0). In the synthesis of butyl butyrate in anhydrous medium, 85% ester conversion was achieved at 37 °C after 8 h reaction. Thus, Sc-WCL showed to be a promising biocatalyst because it is cheaper than the isolated and purified lipases. |
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