Detection and Expression of Biosynthetic Genes in Actinobacteria ...

BERVANAKIS, G.Chapter 3: RESULTS3.2.3.2 Liquid Fermentations Supplemented with Refined OilsActinobacterial cultures showing low antimicrobial activities in liquid media werefermented in media supplemented with refined oils to determine their usefulness asadditives in enhancing liquid fermentations. In the case of cultures A2707 and A0347,higher activities were detected against the same pathogen when grown in oilsupplementedfermentations than in liquid media alone (Tables 50 and 53). Withisolate A3675 incorporation of refined oils resulted in additional antibacterial activitynot detected in liquid media alone. A summary of the effect of addition of specificrefined oils on the production with 3 cultures is listed in table 53. The refined oilstested in this study exhibited an enhancing effect from low yielding metaboliteproducing actinobacterial liquid fermentations (Table 53). A limitation of thispreliminary screening experiment was that extracts from the uninoculated mediacontaining the refined oils were not obtained, thus the anti-bacterial activity attainedcannot conclusively be said to be due to the oils as the oils themselves are known tocontain antimicrobial activities.Table 53. Well-Type anti-bacterial assay of mycelium extracted metabolitesfrom actinobacterial liquid-oil fermentations after 10 days incubation.Zones of Inhibition^Medium Type* A3675 A2707 A0347IM25 + No Inoculum - - -IM25 + VO +++ +++ +++IM25 + SUN +++ +++ +++IM25 + OLV +++ ++ ++IM25 + HAZ ++ +++ ++IM25 + WAL ++ +++ ++IM25 + SAF ++ +++ +++IM25 + SOY ++ ++ +++IM25 + ALM ++ +++ ++*Fermentation Media Key: IM25 Liquid Media, VO = Vegetable Oil., SUN =Sunflower Oil., OLV = Olive Oil., HAZ = Hazelnut Oil., WAL = Walnut Oil.,SAF = Safflower Oil., SOY = Soya Oil., ALM = Almond Oil.^ Zones of Inhibition: + 8 – 15 mm, ++ 16 – 25 mm, +++ >25 mm,- no inhibition^ Activity was measured against M. luteus_____________________________________________________________________102