Fig. 5

Enhancement of retinol production through mining and evaluation of endogenous and exogenous alcohol dehydrogenases and investigation of the role of antioxidant BHT. a Effect of overexpressing endogenous or exogenous dehydrogenases on retinol formation. b Retinoids production by the engineered yeast strains in the absence and presence of BHT. The error bars represent standard deviations calculated from triplicate experiments and statistical significance of the different retinol levels in comparison with the control was evaluated using Student’s t test (*, P < 0.05; **, P < 0.01). ‘+’ represents the introduction of exogenous genes or overexpression of endogenous genes, while its number represents the copy number of the respective gene in the yeast strain