Evaluating the effect of microbial stimulation and oxidative stress on increasing β-Carotene production in Blakeslea trispora

β-carotene is a lipophilic pigment that belongs to the carotenoid family, produced by plants and microorganisms as a secondary metabolite, and is the most widely utilized carotenoid in the industry. Blakeslea trispora is one of the most significant industrial sources of β-carotene production among microorganisms. The present study aims to investigate the effect of K. rhizophila as a microbial stimulant and butylated hydroxytoluene (BHT) as oxidative stress on increasing β-carotene production in B. trispora. B. trispora was cultivated in the production medium with and without butylated hydroxytoluene (BHT), and after 24 hours, 10 % K. rhizophila cultures with 1011 CFU/mL were added to each medium and incubated for another 4 days. The percentage of carotenoid isomers produced in each sample was determined using high-performance liquid chromatography (HPLC). K. rhizophila and BHT, each alone, could increase carotenoid production by 2.3 and 2.4 times (respectively) compared to the control. The maximum concentration of carotenoids (793 mg/L) was found in samples containing both BHT and K. rhizophila, representing a 7.5-fold increase over the control sample. HPLC analysis of carotenoids showed two prominent peaks, including β-carotene and γ-carotene. The main carotenoid was β-carotene and was found in all samples, followed by a lesser amount of γ-carotene. Overall, microbial stimulation and oxidative stress were effective strategies for increasing β-carotene production in this microorganism.