Effect of physical factors on the production of gamma-decalactone by immobilized cells of Sporidiobolus salmonicolor

The effects of some physical factors, including preculture time, media init ial pH and bead concentrations, on the production of gamma-decalactone by i mmobilized Sporidiobolus salmonicolor CCRC 21975 within calcium alginate be ads were investigated. Long-term reuse and stability of the immobilized pre paration were also examined. Regardless of the preculture time, no signific ant difference in the production of gamma-decalactone by immobilized S. sal monicolor cells was observed as long as the initial populations of the entr apped cells were the same. Calcium alginate-immobilized S. salmonicolor cel ls showed improved tolerance to perturbations in external pH and produced m ore gamma-decalactone than did free cells. The patterns of changes in S. sa lmonicolor cells inside or outside the gel beads as well as production of g amma-decalactone by immobilized S. salmonicolor did not vary significantly with bead concentration. Furthermore, after reuse of the calcium alginate-i mmobilized S. salmonicolor cells for 13 consecutive 4-day batch fermentatio ns, no bead leakage was detected. The production of gamma-decalactone in th e 13th cycle was about 58.4% of that in the first cycle. (C) 1999 Elsevier Science Ltd. All rights reserved.