PRODUCTION OF BENZALDEHYDE BY SEVERAL STRAINS OF ISCHNODERMA-BENZOINUM

Three strains of Ischnoderma benzoinum were cultivated on a medium sup plemented with L-phenylalanine as a precursor, in order to produce ben zaldehyde, bitter almond aroma. Each strain was characterized by it ow n aromatic profil: I. benzoinum CBS 311.29 produced 158 mg L(-1) of be nzaldehyde and 25 mg L(-1) of 4-methoxy-benzaldehyde in 28 d., whereas benzaldehyde concentration didn't exceed 16 mg L(-1) for I. b. CBS 75 2.83. Moreover the strain ATCC 26314 accumulated both phenylethanol (3 60 mg L(-1)) and benzaldehyde (146 mg L(-1)) in 28 d. but no traces of 4-methoxy-benzaldehyde. Among these three strains, I. b. CBS 311.29 h ad the best growth and the highest benzaldehyde production. A study of carbon sources and pH was carried out with this strain to improve the production of bitter almond aroma: results showed that glucose was th e preferential carbon source and that growth and bioconversion were op timal with an initial pH of 6. Finally, contrary to the strains of CBS , I. b. ATCC 26314 was able to accumulate 450 mg.L(-1) of phenylethano l, rose-like aroma; this compound is an intermediate between L-phenyla lanine and benzaldehyde. Phenylethanol accumulation could promote benz aldehyde production by this strain.