Influence of imidazole on carotenoids production
The specific production of lycopene can be promoted by adding compounds which inhibit the action of enzyme lycopene-cyclase that is responsible for cyclization of the ends of the chain to the subsequent production of β-carotene.
When concentrations (50–500 ppm) of imidazole were evaluated, the highest concentration of lycopene (6.82 mg/l)was
obtained by adding imidazole 250 ppm at 24 h of fermentation . At the concentrations (375 and 500 ppm),the microorganisms could not assimilate imidazole, in some cases due to inhibition of microbial growth.
Kinetic parameters
Several reports indicated the pigment production by microorganisms such as fungi, yeasts and bacteria,however,few
studies have been conducted on pigment production in solid-state fermentation,Furthermore,specific production of lycopene is difficult because this carotene is a precursor in the synthesis of β-carotene and others compounds. Choudhari,
Laxmi, and Singhal(2008) evaluated the use of stimulators and inhibitors on the production of β-carotene and lycopene
by Blakeslea trispora NRLL 2895 and 2896, and reported lycopene up to 269.66 +2.23 mg/l, but in our studies showed
0.021+0.00054 mg/l lycopene. The difference between the yields may be due to the fermentation conditions and mainly
of microorganism employed. The profiles of biomass production,glucose consumption and the lycopene concentration were modeled in order to define the theoretical kinetic parameters;which were correlated with the experimental values in order to validate and control the bioprocess. There is a correlation coefficient between values and theory values of biomassof 0.995, substrate consumption of 0.9942 and lycopene production of 0.91. The productivity was evaluated at 24 h of FES;the productivity of lycopene under conditions evaluated is 0.0063 g/h and theoretical values of 0.0033g/h