Extracellular serine proteases by Acremonium sp. L1-4B isolated from Antarctica: Overproduction using cactus pear extract with response surface methodology

• Published in: Biocatalysis and Agricultural Biotechnology
• Main Authors: Evaristo da Silva Nascimento, Talita Camila, Sena, Amanda Reges de, Galindo Gomes, Jose Erick, Santos, Wellington Leal dos, Agamez Montalvo, Gualberto Segundo, Tambourgi, Elias Basile, Medeiros, Erika Valente de, Sette, Lara Duraes, Pessoa Junior, Adalberto, Moreira, Keila Aparecida
• Other Authors: Universidade Estadual Paulista (UNESP)
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier B.V. 2015
• Subjects: Filamentous fungus; Psychrophilic microorganisms; Cactus; Optimization; Bioconversion; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/11449/165053; https://doi.org/10.1016/j.bcab.2015.10.006

Acremonium sp. L1-4B isolated from lichen in Antarctica was used to produce extracellular proteases through submerged fermentation using cactus pear extract (Opuntia ficus-indica Mill.). A 2(3) factorial design was applied to optimize the protease production using three independent variables, namely temperature, pH and concentration of yeast extract, was also used a Central Composite Design (CCD) under Response Surface Methodology (RSM). All variables and interactions analyzed in the factorial design were significant or marginally significant, a Central Composite Design was developed, and the Response Surface Methodology towards the highest point it was established. The experimental model was validated under 14 degrees C, pH 7.54, and 0.55% yeast extract, showing a protease activity of 447.65 +/- 2.6 U/mL by a prediction model of 445.48 U/mL. The enzyme showed a molecular weight of 59 kDa; it was inhibited in the presence of PMSF (serine protease); it presented optimal conditions at pH 8.0 and 50 degrees C; it remained stable at pH in the 3.0-9.0 range and between 10 and 40 degrees C; it showed a tolerance to 3000 mM NaCl as well as to surfactants, hydrogen peroxide and urea at 5%. This paper presents a proposal for an economically attractive production methodology using cactus pear as a primary source of carbon. In addition, the protease secreted by Acremonium sp. L1-4B presented a combination of biochemical characteristics that grants a promising variability of biotechnological applications. (C) 2015 Elsevier Ltd. All rights reserved.