• Journal of Microbiology and Biotechnology
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• v.6 no.2
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• pp.137-141
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• 1996

Acetoin and ammonia, the precursors of tetramethylpyrazine (TMP) having "meaty" or "roasted" flavors, were produced by the culture of Lactococcus lactis ssp. lactis biovar. diacetilactis FC1 in free and immobilized cell systems. Cells were immobilized using k-carrageenan and then were incubated at $34^{\circ}C$. The TMP productivity (0.34 g/l) and the conversion ratio (9.3%) of acetoin to TMP of the immobilized cell system were higher than those (0.24 g/l, 7.0%) of the free cell system. When the beads were activated for 12 h, the productivity of acetoin and TMP increased slightly.