OPTIMIZATION OF CULTURE MEDIUM COMPOSITIONFOR PROTEOLYTIC ENZYME PRODUCTION

H. EL-FADALY, B. SEVELL7~ I~MD L. NYESTE‘I’D Bndape~t, H-152l Gellert Ter 4. Hungary

SummaryOptimization of the culture medium composition for a Bacillus strain growing on soybean meal at 55°C was carried out by two different designs of an orthogonal array. Data showed effective improvement of the medium composition capable of increasing the enzyme production to well over 400 TN/mi culture fluid.

IntroductionRecently, the study of the thermopiles and their enzymes have attracted a lot of interest because of their therostability and unique kinetics. The proteolytic enzymes are a most important group from economic viewpoint in their biotechnological application.Optimization and control of biotechnological process-development are recently becoming important. Numerous studies were carried out to investigate the influence of medium components (carbon, nitrogen, and phosphate) upon .. the growth of proteinase producing bacilli. Several methods of optimization of medium composition have been reported. The objective of the present work as a part of our research programme is to optimize the culture medium composition in order to maximize the enzyme production rate.

Materials and MethodsILicrobia.l strain: Thermophilic Bacillus strain, E52 was originally isolated from Egyptian soil (1]Culture medium: The culture medium used was given by other authors (2]. For cultivation in shake flasks, a G—25 rotary shaker (New Brunswick Sc.CO.( was used. The incubation was at 300 rpm and 55°C in 250 ml Erlenmeyer flask containing 50 ml medium. The inoculation was 10% (v/v( of a 10 h old culture grown on the same medium.Analytical procedure: Microbial growth (OD) was photometerically measured at 620 nm after a 25 time dilution. Enzyme activity was quantitatively estimated by the casein digestion method Experimental design: Three components of the medium (C, N, P(were selected as factors for the medium optimization.First design: Three factor two level orthogonal factorial design was

used. The effect of each factor on the enzyme production rate (gradient) was evaluated. Second design: Two factor three level orthogonal composite factorial design was constructed (4].

------------------------------------------------------------------------Optimization of culture medium composition for

proteolytic enzyme production15/12/1993, 51المؤتمر الدولي للحراريات بنويزيالند, الصفحات

حسين عبدالله محمد الفضالى أ.د.Sevella,B - الجامعة الفنية ببوادابست Nyeste, L - الجامعة الفنية ببوادابست