PROCESS DEVELOPMENT FOR THE PRODUCTION OF A THERMOSTABLE STERYL GLUCOSIDASE IN ESCHERICHIA COLI

FLORENCIA EBERHARDT; LUCIANA PAOLETTI; ANDRES AGUIRRE; SALVADOR PEIRU; HUGO G. MENZELLA

Buenos Aires

Congreso; SAIB 2017; 2017

SAIB

Biodiesels are renewable fuels consisting of fatty acid methyl esters synthesized via transesterification of oils and fats with short chain alcohols. They offer several technicaladvantages over petrodiesel, but some unwanted side products that form insoluble contaminants are also generated. These insoluble precipitates consist mainly on sterile glycosides (SGs). Our working group has described an efficient method for the removal of SGs of biodiesel based on the use of an enzyme with steryl glycosidase activity. The SGase is a thermostable β-glucosidase from Thermococcus litoralis, which was expressed in Escherichia coli. The production process has been optimized through the use of different promoters, the coexpression of molecular chaperones and development of a fed-batch process, reaching a title 260U/ml and productivity 36 U/ml/hour. In this work we describe the effect of using different carbon sources (glucose, glycerol, crude glycerol, sucrose and molasses) in high cell density fermentations of E. coli. Furthermore the effects on the production of the enzyme for different feeding strategies and different C/N ratios at the stage of post-induction were analyzed. Changes in fermentation conditions increased productivity 1.7 times, which directly impacts on the costs of the industrial process for the treatment of biodiesel.