RESUMEN
In view of the paucity of knowledge on the microbial side chain degradation of some phytosterols in favour of the formation of 1,4- androstenedione and 1,4-androstadiene-3,17-dione [AD and ADD] by immobilized cells, the present work described a successful conversion of beta-sitosterol and the total sterols of sunflower oil to AD and ADD. Best conversion estimates [40.64,. 12.3% and 39.43, 10.43% for both AD and ADD] were achieved on performing the process in laboratory stirred fermentor using the fungal cells immobilized on agar agar [4%] at aeration rate equivalent to 1 v/v/min, cell loading 5.7 g% and 1 cm2 bead size
Asunto(s)
Micosis , División Celular , Técnicas de Cultivo de Célula , Andrógenos , Sitoesteroles , Fitosteroles , Cromatografía de Gases , BiotransformaciónRESUMEN
The induced cells of Aspergillus nidulans were homogenized with alumina and centrifuged for obtaining 11-alpha-hydroxylase. The results showed that the maximum 11-alpha-hydroxyprogetreone yield [98.5%] was obtained by using phosphate buffer at pH 7, transformation time 2 hr, at 35C, enzyme ratio [1:20] and Km value 6.15 mg/100 ml. The effect of some activators and inhibitors on 11-alpha-hydroxylase activity were also investigated. While, Mg+2, Co+2, Fe+2 and chloramphenicol appeared to be good inducers and Zn+2, Hg+2 and cyclohexamide showed different inhibitory effects. The 11-alpha- hydroxylase enzyme produced by A. nidulans was observed to be NADPH dependent
Asunto(s)
Oxigenasas de Función Mixta , Biotransformación , Activación Enzimática , Hidroxiprogesteronas , Inhibidores Enzimáticos , Zinc , Cobre , Magnesio , Hierro , EsteroidesRESUMEN
Immobilized spores and mycelium of M. racemosus NRRL 3639 were used to transform progesterone to II-alpha-hydroxy-progesterone [II- alpha- HP], where different fermentation parameters; namely, alginate concentration, time course, different progesterone levels, progesterone coimmobilization, semi-continuous transformation, pH values of the used buffer and addition of some activators, were investigated. The results showed that good yield of II-alpha-hydroxy- progesterone was obtained by using 3% w/v alginate concentration, 48-hour transformation period and 20 mg progesterone, whereas the optimal progesterone concentration for the immobilized spores was 30 mg/50 ml medium. On the other hand, coimmobilization using 100 mg progesterone/10 g wet mycelium at pH 6 and enhancement by MgSO4.7H2O, FeSO4.7H2O and riboflavin gave better yield of II-alpha-HP
Asunto(s)
Mucor , Biotransformación , Mucormicosis , Hidroxiprogesteronas , Fermentación , Esporas FúngicasRESUMEN
The filamentous fungus Mucor racemosus NRRL 3639 efficiently hydroxylated exogenous progesterone to its II-alpha- hydroxy derivative HP. The studies of some parameters affecting the transformation reaction were carried out involving the suitability of the fermentation medium, transformation period, pH, progesterone concentration, addition of some vitamins of B group, micro- and microelements and some steroids as inducers. The results showed that the suitability of Kenawy's medium with pH 6, progesterone concentration 10 mg/50 ml, 48-hour transformation period and II-alpha- HP as inducer, riboflavin 1 mg/50 ml, potassium ferricyanide 1 mg/50 ml, [Mg+2, Fe+2, Mn+2, PO4-3] ions gave the maximum bioconversion reaction [74.3%]