EFFECT OF PHYSICAL FACTORS ON ACETIC ACID PRODUCTION IN BRETTANOMYCES STRAINS

Four species of Brettanomyces ( intermedius , bruxellensis , custersianus , clausenii ) were examined to ascertain their acetic acid production capacity. The results showed that B. bruxellensis was the strain with the best volumetric productivity  and  specific  production  rate  (P = 0.065 gL −1   h −1 ;  V p   = 0.43 gg −1 h −1 ). The best kinetic parameters were reached (P = 0.133 gL −1   h −1 ; Y p/s   = 0.23; P max   = 11.64 gL −1 )  at  an  airflow  of  288 Lh −1   (0.6 vvm,  OTR = 124 mgO 2 L −1   h −1 ), and substrate inhibition was not observed. The influence of temperature and agitation on acetic acid production by B. bruxellensis in a glucose medium was investigated at different levels, 26, 30, 34C and 250, 350, 450 rpm, respectively. Temperature and agitation were shown to be deci‐sive factors ( P  < 0.05) in acetic acid production at 288 Lh −1 (0.6 vvm, OTR = 124 mgO 2 L −1   h). The optimal conditions for a high volumetric productivity were 30C and 250 rpm, respectively.