ABSTRACT
Trichoderma atroviride IMI 206040 synthesizes the coconut lactone 6-pentyl-α-pyrone (6-PAP) de novo and Aspergillus niger DSM 821 produces the rose-like flavour compound 2-phenylethanol (2-PE) from the precursor l-phenylalanine. Here, microparticles of different chemical composition and nominal particle diameter in the range 5-250 µm were added to shake-flask cultures of both fungi to investigate the particles' effect on product formation. Maximum 2-PE concentration increased by a factor of 1.3 to 1430 mg/l with the addition of 2% w/v talc (40 µm diameter). Maximum 6-PAP concentration increased by a factor of 2 to 40 mg/l with the addition of 2% w/v iron (II, III) oxide. The influence of ions leaching out of the particles was investigated by cultivating the fungi in leached particle medium. For the first time, the positive effect of the microparticle-enhanced cultivation (MPEC) technique on the microbial production of volatile metabolites, here flavour compounds from submerged fungal cultures, is demonstrated. The effect is strain- and particle-specific.
Subject(s)
Aspergillus niger/metabolism , Batch Cell Culture Techniques/methods , Phenylalanine/chemistry , Phenylethyl Alcohol/metabolism , Pyrones/metabolism , Trichoderma/metabolism , Aspergillus niger/genetics , Batch Cell Culture Techniques/instrumentation , Particle Size , Phenylalanine/metabolism , Trichoderma/geneticsABSTRACT
Prostaglandins (PGs) act as potent local hormones in nearly all tissues of the human body and are used for various medical applications. Heterologous expression of PG endoperoxide H-synthase from the alga, Gracilaria vermiculophylla, into E. coli and the application of this strain in biotransformation experiments resulted in a highly efficient conversion of arachidonic acid (ARA) yielding up to 130 mg natural PGs l(-1) in a laboratory scale approach. Detailed analyses of the products and production kinetics were performed, confirming a rapid conversion of ARA to PGs.