Screening　from　40　microorganisms　belonging　to　different　taxonomical　groups　(Saccharomyces　cerevisiae,　Lactoballius,　Streptococcus　faecalis　and　Candida　albicans)　was　performed　to　select　the　strain　with　high　production　rate　of　R-(-)-mandelic　acid　(R-MA).　A　sp.　strain　S.　cerevisiae　FD11b　with　high　yield　and　enantiomeric　excess　(e.e.)　and　little　byproducts　was　obtained　by　means　of　UV-mutation　breeding.　In　the　optimal　conditions　of　pH　6.5,　32　degrees　C,　anaerobic　and　glucose　supply　rate　(F-glu)　0.0833　mmol　gdw(-1)　h(-1),　the　strain　FD11b　showed　a　high　specific　MA　production　rate　(q(p)　=　0.35　mmol　gdw(-1)　h(-1))　and　enantioselectivity　(e.e.　=　97.1%).　The　phenylglyoxylic　acid　(PGA)　concentration　showed　a　remarkable　effect　on　the　apparent　activity　of　MA　dehydrogenase.　The　specific　production　rate　(qp)　reached　the　maximum　at　30-40　mM　of　PGA　concentrations.　At　higher　concentrations　of　PGA　more　than　40　mM,　the　qp　decreased　obviously　in　a　linear　way.　However,　the　e.e.　of　R-MA　kept　about　95-96.5%,　when　the　PGA　concentration　was　below　60　mM,　even　at　the　concentration　of　PGA　80　mM,　the　e.e.　was　still　higher　than　90%.　A　modified　Monod　type　equation　based　on　a　hypothesis　of　substrate　inhibition　could　fit　the　experimental　data　well.　The　estimated　maximum　specific　production　rate　(qp,)　and　saturation　constant　(K-s)　were　0.431　mmol　gdw(-1)　h(-1)　and　5.88　mm,　respectively.　(c)　2005　Elsevier　Inc.　All　rights　reserved.