Biotechnology for the production of essential oils, flavours and volatile isolates. A review.

Abstract

Various applications of biotechnological methods for the production of volatile compounds useful to the food and pharmaceutical industries are discussed. The yields obtained from intact or genetically modified plants are compared to those achieved by microbial methods. Plant yields are too low for the products to compete commercially to those synthesized chemically. Still lower yields are obtained with in vitro-cultured plant tissues. Trangenic plants with altered methylerythritol path gave 50% more essential oil in the best case. The 100-fold increases in shikimate-derived volatiles, obtained with overexpressed alcohol dehydrogenase and five-fold more C6 volatle aldehydes and 2-phenylethanol, were produced with overexpressed lipoxygenase and 2-phenylethanol dehydrogenase, respectively. However, the most spectacular yields were observed with biotransformations catalysed by microorganisms. Kluyveromyces marxianus, produces over 26 g/l 2-phenylethanol from phenyalanine, whereas Candida sorbophila, Mucor circillenoides or Yarrowia lipolytica can produce 5-40 g/l g-decalactone from ricinoleic acid. Vanillin production from ferulic acid is in the range 12-60 g/l with Amycolatopsis and Streptomyces species. Vanillin can be produced at 5 g/l by Escherichia coli and amorphadiene yields of 37 g/l have been observed with Saccharomyces cerevisiae, both with the genetically overexpressed methyl-erythritol path. Genetically engineered b-oxidation genes result in yields of 10 g/l g-decalactone byYarrowia lipolytica and up to 80 g/l dicaboxylic acids by various yeasts. These results far exceed the theoretical limit of about 1 g/l required for consideration of a procedure as a commercially interesting process, alternative to chemical sythesis.

Processing, Valorization and Application of Bio-Waste Derived Compounds from Potato, Tomato, Olive and Cereals: A Review

“…For example, those products are called 'cold pressed essential oils'. Essential oils can also be recovered using strong organic solvents, such as hexane or ethyl acetate [63,64]. Moreover, biotechnological approaches are used to create more volatiles in the product before they are recovered, as it is well known that aroma compounds are produced in secondary paths of vegetable metabolism.…”

“…Moreover, biotechnological approaches are used to create more volatiles in the product before they are recovered, as it is well known that aroma compounds are produced in secondary paths of vegetable metabolism. Enhancing some pathways of the metabolism, e.g., by addition of external enzymes such as beta-glucosidases, can lead to the production of more volatiles [63]. An interesting technology to recover volatiles in mild conditions is the Spinning Cone Colum [65].…”

Production of essential oils from in vitro cultures of Caryopteris species and comparison of their concentrations with in vivo plants

“…As compared to field cultivation, in vitro techniques offer the possibility of continuous production of large amounts of chemically uniform biomass independently of wild resources and environmental factors (Murthy et al 2014). As far as essential oils are concerned, in vitro cultivation also gives the possibility to obtain novel compounds, previously not reported in intact plants (Gounaris 2010;Gonçalves and Romano 2013;Marchev et al 2014). Since the accumulation of volatile constituents was shown to be positively correlated with cell differentiation, most experiments aimed at establishing plant in vitro systems for essential oil production were conducted with the use of organ cultures.…”

“…Since the accumulation of volatile constituents was shown to be positively correlated with cell differentiation, most experiments aimed at establishing plant in vitro systems for essential oil production were conducted with the use of organ cultures. In this regard, adventitious and hairy roots are especially useful due to their fast growth and high yield of secondary metabolites (Gounaris 2010;Baque et al 2012). Nevertheless, essential oils are often found in substantial amounts also in shoot cultures, such as those of Arnica montana (Petrova et al 2012), Thymus caespititius (Mendes et al 2013) and Mentha sp.…”

“…Miq., Caryopteris mongolica Bunge and Caryopteris 9 clandonensis Simmonds, a hybrid between the two previous plants which so far has not been studied with respect to essential oil production. Given that organogenesis is known to positively affect the accumulation of volatile compounds (Gounaris 2010;Gonçalves and Romano 2013), the current research focused especially on establishing organ cultures. Gas chromatography coupled with mass spectrometry (GC-MS) was used to investigate the composition of hydrodistilled essential oil obtained from aerial and underground parts of Caryopteris intact plants, as well as shoots and roots maintained under in vitro conditions.…”