Photoenzymatic Production of Next Generation Biofuels from Natural Triglycerides Combining a Hydrolase and a Photodecarboxylase

Abstract

A photobiocatalytic cascade transforming natural triglycerides into alkanes/alkenes is proposed. Starting from natural triglycerides, free fatty acids have been obtained using lipases. The free fatty acids were then, in a photoenzymatic step, decarboxylated into the C1‐shortened alkanes using a recently described photodecarboxylase from Chlorella variabilis NC64A. This cascade produced alkanes from various natural (waste) oils in significant amounts (up to 24 g L−1) and may provide a basis for valorisation of waste oils into a next generation of biodiesel.

Intensification of Photobiocatalytic Decarboxylation of Fatty Acids for the Production of Biodiesel

“…In our experiments the turnover numbers for Cv FAP (TON=mol product ×mol Cv FAP −1 ) never exceeded 9.000. These turnover numbers are well in the range of TONs previously observed for Cv FAP [10–15] indicating that the light intensity itself is not the main parameter for Cv FAP inactivation. This supports the Cv FAP inactivation mechanism proposed by Scrutton and co‐workers, assuming that intermediate radical species occurring in the catalytic mechanism may cause inactivation of the biocatalyst [6] …”

“…Therefore, we became very interested in the recently reported photoactivated fatty acid decarboxylase from Chlorella variabilis NC64A ( Cv FAP) [4] . Upon illumination with visible light ( λ =450 nm) Cv FAP catalyzes the decarboxylation of a broad range of fatty acids [4–15] . However, photochemical processes are severely limited by current reactor designs involving external illumination.…”

Photo‐biocatalytic Cascades: Combining Chemical and Enzymatic Transformations Fueled by Light

“…In a follow‐up study, the feasibility of producing alkanes originated from different natural (waste) oils was evaluated by performing whole‐cell biotransformations under blue‐light exposure. As indicated by the authors, product concentrations of up to 24 g L −1 could be achieved within 48 h [92] . Besides the described production of alkanes from triglycerides, Ma and co‐workers proposed a bienzymatic cascade converting castor oil into ( R , Z )‐octadec‐9‐en‐7‐ol (Scheme 15B) [95] .…”

“… Different photo‐biocatalytic cascades comprising a photo‐decarboxylation step catalyzed by Cv FAP [93,92,116] …”

“…Recently, a fatty acid photodecarboxylase (FAP) from microalgae has gained increasing attention due to their ability to catalyze a light‐mediated decarboxylation of fatty acids, [91] which may be applied for sustainable biofuel production from natural resources [92] . Under blue light irradiation, Cv FAP from Chlorella variabilis converted long‐chain fatty acids into the corresponding alkanes with highly promising turnover numbers and almost full conversion [93] .…”