This medium is prepared by completely replacing animal based peptones with vegetable peptones that makes the medium free of BSE/TSE risks. Spirit Blue HiVeg Agar is the modification of Spirit Blue Agar which is prepared according to the formulation of Starr (1). It is a basal medium to which lipid substrate is added for the detection, enumeration and study of lipolytic microorganisms. Starr reported spirit blue to be inert and did not exhibit any toxic effect, hence was suggested to be an ideal indicator of lipolysis.
The lipase substrates recommended includes lipid sources such as cotton seed meal, cream, olive oil etc. Since lipid is insoluble in aqueous phase, a satisfactory emulsion can be prepared by dissolving in suitable emulsifiers. For preparing emulsion, a 10 gram of gum acacia or 1 ml polysorbate 80 may be dissolved in 400 ml warm distilled water, then 100 ml cotton seed or olive oil or substrate being used should be added and agitated vigorously to emulsify. This emulsified substrate can be used for studying lipolysis.
HiVeg hydrolysate and yeast extract are the sources of carbon, nitrogen, vitamins and minerals. Spirit blue is the indicator of lipolysis. Lipolytic microorganisms produce inducible lipase enzyme which further hydrolyses the available emulsified lipid substrate in the medium and forms colonies with halos indicating lipolysis.
Directions:Suspend 32.15 grams in 1000 ml distilled water. Heat to boiling to dissolve the medium completely. Sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes. Cool to 50°C and add 30ml lipase substrate slowly while agitating to obtain an even distribution.