Title : Optimized biocatalytic process for 13-HPOs production from hempseed oil: A step toward natural green leaf volatiles synthesis
Abstract:
Natural green leaf volatiles (GLVs), such as short-chain aldehydes responsible for the characteristic fresh green aroma, are widely used in the flavor and food industries. Their sustainable production can be achieved through a biocatalytic cascade starting from vegetable oils. In this process, triacylglycerols are first hydrolyzed by a lipase to release free polyunsaturated fatty acids (PUFAs), which are subsequently oxygenated by a lipoxygenase (LOX) to yield corresponding hydroperoxides (HPOs). HPOs can then be converted by a hydroperoxide lyase to produce volatile aldehydes and oxoacids.
To meet the growing demand for such natural compounds, the production of 13-hydroperoxyoctadecadienoic acid (13-HPO) from hempseed oil (Cannabis sativa), a rich source of linoleic and linolenic acids, was investigated. The lipolysis step was optimized using response surface methodology (RSM) to evaluate the effects of pH, temperature, duration, oil/aqueous ratio, and lipase load on the hydrolysis rate. Under optimal conditions, a commercial Candida rugosa lipase (CRL) achieved a hydrolysis rate of 97.2 ± 3.8 %.
The resulting hydrolysate, containing the released PUFAs, was then directly used as substrate for the second step catalyzed by a commercial soybean 13-lipoxygenase (Glycine max.) to form 13-HPOs. Following a RSM design, the LOX-catalyzed step was optimized, by evaluating the effect of temperature, duration, oxygen flow, LOX load, and hydrolysate load on the conversion. The optimized conditions led to an 84.15 ± 0.03 % conversion of PUFAs into 13-HPOs.
These results confirm the efficiency of the sequential CRL–LOX biocatalytic system for the selective production of 13-HPO from hempseed oil.
