Cultivation and Preliminary Screening of Some Microalgae and Cyanobacteria for Biotransformation of Coumarins and Flavonoids

Microalgae and cyanobacteria are microorganisms that have a promising role as a recent approach in drug discovery. Their significance is due to their broad applications in the medical field as antifungal, antibacterial and antiviral agents. Seven cultures of microalgae and cyanobacteria; three chlorophytes (green microalgae): Chlorella vulgaris, Monoraphidium griffithii and Scenedesmus dimorphus and four cyanobacteria: Anabaena variabilis, Nostoc carneum, Oscillatoria limnetica and Spirulina platensis were isolated from Delta region, these species were cultivated in BG11 media for 21 days. Growth was assessed as culture optical density at 24 hours intervals. The different growth phases were illustrated by the growth curve, the maximum growth was recognized on day 21 representing the beginning of the stationary phase of growth. The optical density at 680 nm for microalgae C. vulgaris, M. griffithii and S. dimorphus was 1.32, 1.67 and 1.53 nm, respectively. The optical density at 760 nm for the cyanobacteria A. variabilis, N. carneum, O. limnetica and S. platensis was recorded as1.91, 2.23, 1.52 and 1.81 nm, respectively.HPLC- fingerprint pattern of methanol extracts of the seven cultures was examined using High-Performance Liquid Chromatography (HPLC(. Thin Layer Chromatography (TLC) visual inspection was carried out for all extracts. These isolates were screened for their potential for biotransformation of coumarins (coumarin and umbelliferone) and flavonoids (naringenin and chrysin). For all investigated strains, methylene chloride, ethyl acetate and n-butanol extracts of the coumarin supplemented cultures gave positive results as screened on TLC plates. However, naringenin exhibited positive results with S. platensis only.