ITACONIC ACID PRODUCTION BY Aspergillus terreus MJL05: CULTURE MEDIUM COMPOSITION EFFECT USING EXPERIMENTAL DESIGN TECHNIQUES

JUY, MARIANA I.; JOAQUÍN A. OREJAS; MARÍA ESTER LUCCA

Barcelona

Congreso; 10th World Congress of Chemical Engineering and 4th European Congress of Applied Biotechnology; 2017

EFCE SPAIN GROUP

Itaconic acid (IA) is an unsaturated dicarbonic organic acid. It can easily be incorporated into polymers and may serve as a substitute for petrochemical-based acrylic or methacrylic acid. It is used as a comonomer in resins and also in the manufacture of synthetic fibres, in coatings, adhesives and thickeners. IA is obtained by carbohydrates fermentation with a filamentous fungus, A. terreus. Glucose is usually used as the only carbon source. In our previous work, A. terreus MJL05 strain was tested in IA production with glycerol as carbon substrate in immobilized systems and stirred liquid cultures and the results obtained showed no significant differences in IA yield. In this work, with the purpose improve the productivity of the process a theoretic-experimental study is described using experimental desing and response surface techniques. The factors to study were initial concentrations of three nutrients (potassium dehydrogenate phosphate, ammonium nitrate and glycerol). The response were IA production, biomass production, conversion of glycerol and yield. The selected procedure was a 23 two-level complete compuest central factorial design that was implemented at two blocks or stages. The statistical analysis of the experimental results allowed define two additional zones which were examined also with a compuest central factorial design but only including two factors (ammonium nitrate and glycerol).Each experiment was carried out in 250 ml Erlenmeyer flasks with 100 ml of medium inoculated with a spore suspension of 108 spores/ml and incubated at 30ºC for 8 days on a rotary shaker at 200 rpm. Influence of each factor and possible interactions between them were analyzed. Depending on initial nutrients concentrations tested, IA final concentration obtained was as low as 2.0 gr.l-1 or increased up to 25.0 gr.l-1. Glycerol transformed in IA was varied between 15 to 55 %. The nitrogen source had a relevant impact on IA production and IA concentration was increased in 10 gr.l-1 by adding a plus of 2 gr.l-1 in the nitrogen concentration source. It might be concluded that IA concentration showed a linear relation respect of biomass and that considering a specific glycerol conversion factor, IA yield referred to carbon source is higher than the corresponding one for biomass.