Promising enzymatic technology on the horizon & the up-scaling of the epoxidation of oil fatty acids for industrial applications
As a collaborative European research & innovation project looking for the development as well as the scale-up of the production of SUStainable bio-BINDer systems for wood-based panels, SUSBIND is addressing the need for more sustainable bio-based binders used for wood-based panel boards in the European furniture industry.
Enzymatic reactions hold great potential to reshape the world, through the processing of agricultural and food industrial wastes, by creating sustainable by-products and favouring environmental rehabilitation. Therefore, the development of technologies for establishing successful enzyme-based processes has been very attractive in recent years to ensure sustainable and environmentally-friendly waste products.
Agricultural and food industry by-products and wastes can be utilized for manufacturing specialty and commodity chemicals, which may lead to the reduction in the dependency on fossil raw materials. Understanding the chemistry of these by-products and developing novel processing techniques has never been so important. This special issue is intended to attract cutting edge original research and recent advances on novel technologies applied to agriculture and food wastes as well as the processing of by-products.
Therefore, in their search for alternative binders produced from renewable resources, SUSBIND partners Instituto de Recursos Naturales y Agrobiología de Sevilla – IRNAS-CSIC (Seville, ES), Centro de Investigaciones Biológicas “Margarita Salas” – CIB-CSIC (Madrid, ES) and JenaBios GmbH (DE), together with Novozymes A/S (DK) recently shared their results in a scientific paper on promising enzymatic technology for epoxidizing complex mixtures of free or methylated fatty acids obtained from representative vegetable oils, under mild and environmentally-friendly conditions.
Enzyme technology broadly involves the production, isolation, purification and use of enzymes (in soluble or immobilized forms) for the ultimate benefit of humankind. In addition, recombinant DNA technology and protein engineering involved in the production of more efficient and useful enzymes are also a part of enzyme technology.
The article published by Frontiers in Bioengineering and Biotechnology, titled ‘High Epoxidation Yields of Vegetable Oil Hydrolyzates and Methyl Esters by Selected Fungal Peroxygenases’, takes into consideration economic aspects, technical suitability and sustainability, and concludes that an industry suitable solution for a bio-based binder ingredient could be based on sunflower oil. The sunflower oil is argued as the best solution for scaling-up the mild and selective production of epoxidized fatty acids using enzymes of the group of unspecific peroxygenases (UPOs), including both wild (e.g. MroUPO and CglUPO) and recombinant (e.g. rHinUPO) UPOs.
Rapeseed, soybean, sunflower or linseed oils are suitable raw materials for lipid compound production (including epoxide-type biobinders)A series of oil-producing plants of global significance are available for the production of renewable lipid epoxides and other oxygenated derivatives. Commercially exploited oil seeds, such as rapeseed, soybean, sunflower, or linseed, exhibited a considerable variation in their fatty acid profiles, which makes them suitable raw materials for the production of different lipid compounds. The hydrolyzated and transesterified products of the above-mentioned vegetable oils were treated with three fungal UPOs to obtain epoxides. The three enzymes were capable of transforming free fatty acids (FAs) and FA methyl esters (FAMEs) from the oils into the corresponding epoxide derivatives, although some significant differences in selectivity toward epoxidation were observed, with CglUPO being generally more selective. The results show that the fungal UPOs elude some of the limitations of other monooxygenases since they are secreted proteins, therefore far more stable, as they only require H2O2 for activation.
Moreover, their recent expression as soluble and active enzymes in Escherichia coli is expanding the number of UPO enzymes available from related genes in sequenced genomes and simultaneously. They enable the rational design of the available UPOs as ad hoc biocatalysts of industrial interest using protein engineering tools. Most noteworthy is the ability of these UPOs, particularly rHinUPO being able to produce triepoxides from these samples.
Unspecific peroxygenase (UPO) enzymes from fungi Marasmius rotula (MroUPO), Chaetomium globosum (CglUPO) and Humicola insolens (HinUPO), among others, are promising biocatalysts for the mild and selective epoxidation of unsaturated lipidsTherefore, UPOs appear as promising biocatalysts for the environmentally-friendly production of reactive fatty-acid epoxides given their self-sufficient monooxygenase activity with high epoxidation selectivity, including recently reported enantioselectivity (in addition to strict regioselectivity) of some of their reactions.
However, in spite of all recent progress in our understanding of UPO catalysis and application, some difficulties still remain to be solved, such as the inactivation by H2O2 which affects enzyme reuse.
This could be solved by the continuous feeding of low H2O2 concentration, or its in situ generation by enzymatic or chemical systems, thus further increasing the concentration of FA substrates and the final epoxide products.
High Epoxidation Yields of Vegetable Oil Hydrolyzates and Methyl Esters by Selected Fungal Peroxygenases
Alejandro González-Benjumea, Gisela Marques, Owik M. Herold-Majumdar, Jan Kiebist, Katrin Scheibner, José C. del Río, Angel T. Martínez and Ana Gutiérrez
Front. Bioeng. Biotechnol., 05 January 2021, OPEN ACCESS, DOI: https://doi.org/10.3389/fbioe.2020.605854