The ability of Neurospora crassa FGSC 4335 in the biotransformation of hydrocortisone was investigated. The microorganism produced two major metabolites after incubation with the substrate for seven days. Each microbial product was purified chromatographically and identified on the basis of spectral data. The products were identified as 11 b, 17 a, 20b, 21-tetrahydroxypregn-4-en-3- one (II) and 11b-hydroxyandrost-4-en-3, 17-dione (III) in the yields of 25% and 18.8%, respectively. Time course study showed the accumulation of both products from the second day of the fermentation and reached to the maximum in the seventh day. Optimum concentration of the substrate, which gave maximum bioconversion efficiency, was 1 mg ml-1 in one batch. Biotransformation was completely inhibited in a concentration above 2.5 mg ml-1.

The potential of microalgae for steroid transformation has been studied less than other microorganisms. They have been applied for the years in the treatment of environmental pollutions and preparation of nutrients. At the first time, Abul-Hajj and Qian indicated the conversion of androstendione (AD) to testosterone with eleven different strains of microalgae. Previtera’s group showed the transformations of progesterone and prednisolone in several microalgal cultures within four studies. In other investigations, steroid substrates were 5?-androstane-3, 17-dione, adrenosterone, androsta-1, 4-diene-3, 17-dione (ADD) and 17?-hydoxy-17?-methylandrosta-1, 4-dien-3-one. Hydrocortisone biotransformation using Nostoc muscorum was also reported with Tabatabie group. In this study, the ability of Nostoc muscorum, blue green algae, for biotransformation of AD and ADD were investigated. This potential has not been previously examined. The selected microalgae was isolated during a screening program from soil samples collected from paddy field of north of Iran. The fermentation media were included BG-11 medium together with AD or ADD 0.05%, separately, as steroid substrates. The experiment was illuminated continuously with fluorescent lamps at 40 µEm-2S-1, and incubated at a temperature of 25±2°C without shaking for ten days. The chloroform extract was loaded on silica gel plates with acetone/hexan (1:1) solvent system. The obtained fractions were further purified by re-chromatography, followed by crystallization. Then, the metabolites and unconverted substrates from each experiment were identified by melting points and spectral methods including 13C NMR, 1H NMR, FTIR and MS. The fermentation reaction of AD with Nostoc muscorum led to accumulation of testosterone in the broth medium. 1-Dehydrotestosterone was the product of ADD bioconversion in the microalgal culture. In both cases, the bioconversion characteristics observed were 17-carbonyl reduction. Thus, the microorganism represented to act selectively at the ketone group on the D-ring of both androstane like steroids.

Callus and suspension cultures of Lavandula angustifolia Mill. (Lamiaceae) were established and the effect of different culture media on growth rate was investigated. Terpenoids added to suspension culture to investigate their biotransformation. All samples were analyzed by gas chromatography (GC) and GC-mass spectroscopy (MS). Octan-1-ol, citronellol, linalool, borneol and geraniol were biotransformed products of octanal, citronellal, linalyl acetate, bornyl acetate and geranyl acetate, respectively. Citronellol, linalool, borneol, and menthol didn't change by L. angustifolia suspension cultures. Blue pigment production by cultures of L. angustifolia was also studied. Ester hydrolysis and oxidation were the main reactions which occurred in biotransformation process, which may be attributed to the presence of related or bifunctional enzymes. This technique is a possible way of the production of expensive or rare compounds from cheap and plentiful substrates.