Synthetic complete drop out medium

l-threonine, 2-ketobutyric acid, (R)- and (S)-aminobutyric acid, (R) and (S)-2-aminobutanol were bought from Sigma-Aldrich Chemie AG (Steinheim, Germany). Yeast Extract Peptone (YPD) medium with 20 g/L glucose was used for growth of the wildtype strain prior to transformation and both bought from Sigma-Aldrich Chemie AG. Synthetic complete (SC) drop out medium (Formedium LTD, Hustanton, England) with 6.7 g/L yeast nitrogen base without amino acids and ammonium sulfate (Sigma-Aldrich Chemie AG), and 20 g/L glucose (Sigma-Aldrich Chemie AG) was used for pre- and main cultures. LB medium for growth of E. coli was supplied from Carl Roth GmbH + Co. KG (Karlsruhe, Germany).

All chemicals were bought from Sigma-Aldrich (St. Louis Missouri, USA) unless stated otherwise. Authentic standard of cembrene was purchased from CHEMOS GmbH & Co. KG (Regenstauf, Germany). Authentic standard of casbene was received from Professor Birger Møller's laboratory at the University of Copenhagen.
LB medium for growth of Escherichia coli was supplied from Carl Roth GmbH + Co. KG (Karlsruhe, Germany), and was supplemented with 100 μg/L of ampicillin for amplification of plasmids. Yeast Extract Peptone Dextrose (YPD) medium with 20 g/L glucose was used for growth of wildtype strains prior to transformation. For preparation of pre- and main cultures we used synthetic complete (SC) drop-out medium (Formedium LTD, Hustanton, England), supplied with 6.7 g/L yeast nitrogen base, 20 g/L glucose and all amino acids necessary for the corresponding auxotrophy.