Growth of and production of γ-decalactone by Sporobolomyces odorus in jar fermentors as affected by pH, aeration and fed-batch technique

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In jar fermentors, Sporobolomyces odorus grew rapidly and entered the stationary growth phase at approximately 72 h of cultivation. During the 192 h fermentation period, pH and DO concentration in the medium first decreased and then increased. A maximum yield of γ-decalactone of 54.6 mg/ l was noted after 120 h of cultivation. Studies on the effects of pH control and aeration rate revealed that maintaining the pH of the medium at 4.0, 5.0, 6.0 or 7.0 neither affected the growth of S. odorus nor improved the yield of γ-decalactone, and that although a larger maximum final population was found in the culture with an aeration rate of 2 vvm, a greater yield of γ-decalactone was noted when aeration rate was maintained at 1.0 or 1.5 vvm. A significant increase in the maximum yield of γ-decalactone was noted in fed-batch culture of S. odorus. The maximum yield of γ-decalactone increased with the number of castor oil hydrolysate feedings. Fed-batch cultivation of S. odorus with additions of castor oil hydrolysate on the 3rd, 4th and 5th d of cultivation resulted in a maximum yield of 208 mg/ l γ-decalactone which was noted after 7 d of cultivation.