Production of Microbial Transglutaminase on Media Made from Sugar Cane Molasses and Glycerol
Oscar M. Portilla-Rivera1, Simón J. Téllez-Luis1, José A. Ramírez de León1 and Manuel Vázquez2*
1Department of Food Science and Technology, UAM Reynosa-Aztlán, Autonomous University of Tamaulipas, Calle 16 y Lago de Chapala s/n, Col. Aztlán, Reynosa, MX-88740 Tamaulipas, Mexico
2Department of Analytical Chemistry, Veterinary Faculty, University of Santiago de Compostela-Campus de Lugo, ES-27002 Lugo, Spain
Article history:
Received October 5, 2007
Accepted December 4, 2007
Key words:
transglutaminase, glycerol, glucose, sugar cane molasses
Summary:
Transglutaminase is an enzyme that catalyses an acyl transfer reaction between γ-carboxamide groups of glutaminyl residues and lysine residues in proteins. Due to this property, this enzyme is used for enhancing textural properties of protein-rich food. The transglutaminase used as food additive is obtained by microorganisms, mainly by Streptoverticillium ladakanum. On the other hand, sugar cane molasses is a viscous liquid rich in noncrystallized carbohydrates (saccharose, glucose and fructose). In this work, the feasibility of using sugar cane molasses as a carbon source for the production of microbial transglutaminase by Streptoverticillium ladakanum NRRL 3191 has been studied. Carbon sources including sugar cane molasses (60 g of total sugars per L), glycerol (60 g/L) and their mixture in a ratio of 1:1 (30 g/L of each) were evaluated. Time course of microbial growth, transglutaminase activity and carbon source consumption were determined every 24 h during 120 h of fermentations at three agitation speeds (200, 300 or 400 rpm). The results showed that with the increase in agitation speed, the biomass concentration increased up to 8.39 g/L in the medium containing sugar cane molasses alone or the mixture of molasses and glycerol. The highest transglutaminase activity was obtained at 400 rpm in the medium containing a mixture of molasses and glycerol, reaching 0.460 U/mL, while in the medium containing sugar cane molasses alone, the activity was 0.240 U/mL, and using glycerol alone it was 0.250 U/mL. These results show that sugar cane molasses is a suitable medium for transglutaminase production when it is combined with glycerol.
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