Microorganisms culture
Another biotechnology method for the synthesis of volatiles is the culture of micrograms. Microorganisms (such as bacteria, fungi, algae, …) are more potent than plant cells in bioreactor conditions [116]. Of course if a substrate biochemically more immediate to the volatile compound, or an immediate precursor with the raw substrate is used in the culture medium, the efficiency will increase. In this case, the method is similar to biotransformation, which will be explained in the next section. for example, 0.4 g/l 2-phenylethanolwhich has a rose-like aroma can be produced by Kluyveromyces marxianus [124]. also 2.8 g/l vanillin was achieved by cultured Aspergillus niger [125].
The table 6 presents a list of some of the volatile compounds produced by cell, hairy roots, and microorganism cultures.