Abstract:S-adenosyl-L-methionine(SAM) was high-value amino acid that had great market potential.To enhance SAM accumulation by inhibiting its consumption,three inhibitors were added during the late fermentation stage of inducible Pichia and constitutive Pichia.Firstly,their influences were investigated,and the differences were compared,and finally,the mechanisms were analyzed.The results showed that addition of Aristeromycin,an inhibitor of S-adenosyl-L-homocysteine hydrolase,contributed to SAM accumulation,but comparatively speaking,the optimum addition level for inducible Pichia was lower,likely because the oxidative stress resulting from methanol metabolism strengthened the dependence of Pichia cell on transmethylation reaction.Supplement of DFMA,an inhibitor of polyamine synthesis,improved SAM accumulation,while the excessive amount of DFMA led to reduction of cell growth and anti-oxidation ability.Addition of acetic acid at 7.5 g/L improved SAM accumulation,through reducing polyamine formation.The three inhibitors mentioned above were proved effective for improvement of SAM production.
