Enhanced production of vanillin flavour metabolites by precursor feeding in cell suspension cultures of Decalepis hamiltonii Wight & Arn., in shake flask culture.

The flavour rich tuberous roots of Decalepis
hamiltonii are known for its edible and medicinal use and
have become endangered due to commercial over-exploitation.
Besides 2-Hydroxy-4-methoxy benzaldehyde
(2H4MB), other flavour metabolites in tuberous roots
include vanillin, 4-Methoxy Cinnamic acid derivatives,
aromatic alcohols etc. So far, there are no reports on the
pathway of 2H4MB biosynthesis nor there is an organized
work on biotransformation using normal and cell suspension
cultures for obtaining these metabolites using precursors.
The main aim of the study is to develop a method
for enhanced production of flavour attributing metabolites
through ferulic acid (FA) feeding to the D. hamiltonii
callus culture medium. Biomass of D. hamiltonii cell suspension
cultures was maximum (200.38 ± 1.56 g/l) by 4th
week. Maximum production of 2H4MB was recorded on
4th week (0.08 ± 0.01 mg/100 g dry weight) as quantified
by HPLC. Addition of 0.1–1.5 mM ferulic acid as precursor
in the culture medium showed significant
(p\0.001) effect on suspension cultures biomass and
respective phenylpropanoid metabolites content and
2H4MB accumulation. The maximum accumulation of
vanillin, 2H4MB, vanillic acid, ferulic acid were of
0.1 ± 0.02 mg/100 g, 0.44 ± 0.01 mg/100 g, 0.52 ±
0.04 mg/100 g, 0.18 ± 0.02 mg/100 g DW respectively in
4 weeks of cultured cells supplemented with 1 mM ferulic
acid as a precursor. The results indicate that, substantial
increase in the levels of flavour metabolites in D. hamiltonii
callus suspension culture was achieved. This would be
having implications in biosynthesis of respective vanilla
flavour attributing metabolites at very high levels for their
large scale production.