The market for industrial enzymes has witnessed constant growth, which is currently around 7% a year, projected to reach $10.5 billion in 2024. Lipases are hydrolase enzymes naturally responsible for triglyceride hydrolysis. They are the most expansively used industrial biocatalysts, with wide application in a broad range of industries. However, these biocatalytic processes are usually limited by the low stability of the enzyme, the half-life time, and the processes required to solve these problems are complex and lack application feasibility at the industrial scale. Emerging technologies create new materials for enzyme carriers and sophisticate the well-known immobilization principles to produce more robust, eco-friendlier, and cheaper biocatalysts. Therefore, this review discusses the trending studies and industrial applications of the materials and protocols for lipase immobilization, analyzing their advantages and disadvantages. Finally, it summarizes the current challenges and potential alternatives for lipases at the industrial level.

Current Status and Future Perspectives of Supports and Protocols for Enzyme Immobilization

The excessive demand for fossil fuels has caused severe environmental impacts, such as GHG-related effects and widespread pollution. Firstly, it is essential to identify the main problems arising from fossil fuel production and consumption, which will enable the search and implementation of technological, sustainable, and economical alternatives to mitigate the current issue. With the modern technological advances in this specific area, the use of biofuels has expanded, given their high potential of production from diverse classes of biomass. Producing biodiesel from microalgae oil specifically, as a way of obtaining clean and renewable energy, can play a significant role in this context, and the process is of high interest to the energy sector. Biodiesels are produced through mixtures of ethyl esters or fatty acid methyl esters, which are generated by the synthesis of oil with alcohol in the presence of the enzyme alcohol lipase. There are clear challenges linked to the new technologies employed to obtain biofuels from microalgae, and there also are strong prospects to these approaches, since they are very energy-efficient and environmentally friendly. Thus being, the present review describes the main aspects associated with biodiesel production from microalgae, highlighting the fundamentals of the technique, the immobilization processes followed, the use of solvents to optimize reaction media, bioreactor systems, as well as the performance optimization of microalgae biodiesel-based engines, while considering important economic and environmental aspects. Future trends in the biofuel scientific research and industry are also included, aiming at fostering discussions on the development of other significant advances in the use of microalgae lipase and oil technology for biodiesel production. 

Biodiesel production from microalgae using lipase-based catalysts: Current challenges and prospects

In the present communication, the simultaneous co-immobilization by covalent binding of lipase A from Candida antarctica (CALA) and lipase B from Candida antarctica (CALB) in glutaraldehyde (GLU) activated chitosan (CHI) was optimized using the Taguchi method. Under optimized conditions (pH 9, 5 mM, 6:1 (protein load/g of support and 1 h), it was possible to reach 80.00 ± 0.01% for the immobilization yield (IY) and 46.01 ± 0.35 U/g for the activity of the derivative (AtD); in this case, load protein and ionic strength were the only statistically significant parameters and, therefore, those that most influenced the immobilization process. Furthermore, at pH 7, CALA-CALB-CHI had a half-life 2–6 times longer than the mixture of CALA and CALB for a temperature range of 50−80 °C. CALA-CALB showed the highest activity at pH 7, whereas CALA-CALB-CHI, except at pH 7, was more active than the soluble lipase mixture in the pH range (5–9), especially at pH 9. CHI, CHI-GLU, and CALA-CALB-CHI were characterized by X-ray powder diffraction (XRPD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Thermogravimetry (TGA), and Energy Dispersive Spectroscopy (EDS), proving the immobilization of CALA and CALB in chitosan. CALA-CALB-CHI derivative evaluated in the kinetic resolution of halohydrins acetates rac-2-bromo-1-(2-chlorophenyl) ethyl acetate (2a) and rac-2-chloro-1-(2,4-dichlorophenyl) ethyl acetate (2b), to produce the corresponding halohydrins 3a-b, which are intermediates in the synthesis of the drugs chlorprelanine (antiarrhythmic) and luliconazol (antifungal), respectively. (S)-bromohydrin 3a was obtained with 79% enantiomeric excess (ee), whereas (S)-chlorohydrin 3b produced with 98% ee, conversion of 46% and E > 200. Additionally, molecular docking was performed to elucidate the hydrolysis interaction reaction between β-halohydrin acetates and lipases CALA-CALB.

Taguchi design-assisted co-immobilization of lipase A and B from Candida antarctica onto chitosan: Characterization, kinetic resolution application, and docking studies

In the present communication, the simultaneous co-immobilization by covalent binding of lipase A from Candida antarctica (CALA) and lipase B from Candida antarctica (CALB) in glutaraldehyde (GLU) activated chitosan (CHI) was optimized using the Taguchi method. Under optimized conditions (pH 9, 5 mM, 6:1 (protein load/g of support and 1 h), it was possible to reach 80.00 ± 0.01% for the immobilization yield (IY) and 46.01 ± 0.35 U/g for the activity of the derivative (AtD); in this case, load protein and ionic strength were the only statistically significant parameters and, therefore, those that most influenced the immobilization process. Furthermore, at pH 7, CALA-CALB-CHI had a half-life 2–6 times longer than the mixture of CALA and CALB for a temperature range of 50−80 °C. CALA-CALB showed the highest activity at pH 7, whereas CALA-CALB-CHI, except at pH 7, was more active than the soluble lipase mixture in the pH range (5–9), especially at pH 9. CHI, CHI-GLU, and CALA-CALB-CHI were characterized by X-ray powder diffraction (XRPD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Thermogravimetry (TGA), and Energy Dispersive Spectroscopy (EDS), proving the immobilization of CALA and CALB in chitosan. CALA-CALB-CHI derivative evaluated in the kinetic resolution of halohydrins acetates rac-2-bromo-1-(2-chlorophenyl) ethyl acetate (2a) and rac-2-chloro-1-(2,4-dichlorophenyl) ethyl acetate (2b), to produce the corresponding halohydrins 3a-b, which are intermediates in the synthesis of the drugs chlorprelanine (antiarrhythmic) and luliconazol (antifungal), respectively. (S)-bromohydrin 3a was obtained with 79% enantiomeric excess (ee), whereas (S)-chlorohydrin 3b produced with 98% ee, conversion of 46% and E > 200. Additionally, molecular docking was performed to elucidate the hydrolysis interaction reaction between β-halohydrin acetates and lipases CALA-CALB. 

Chitosan, a copolymer of glucosamine and N-acetyl glucosamine, is derived from chitin. Chitin is found in cell walls of crustaceans, fungi, insects and in some algae, microorganisms, and some invertebrate animals. Chitosan is emerging as a very important raw material for the synthesis of a wide range of products used for food, medical, pharmaceutical, health care, agriculture, industry, and environmental pollution protection. This review, in line with the focus of this special issue, provides the reader with (1) an overview on different sources of chitin, (2) advances in techniques used to extract chitin and converting it into chitosan, (3) the importance of the inherent characteristics of the chitosan from different sources that makes them suitable for specific applications and, finally, (4) briefly summarizes ways of tailoring chitosan for specific applications. The review also presents the influence of the degree of acetylation (DA) and degree of deacetylation (DDA), molecular weight (Mw) on the physicochemical and biological properties of chitosan, acid-base behavior, biodegradability, solubility, reactivity, among many other properties that determine processability and suitability for specific applications. This is intended to help guide researchers select the right chitosan raw material for their specific applications.

https://www.mdpi.com/2310-2861/8/7/393/pdf?version=1656316892

Roberta Bussons Rodrigues Valério

Papers

Chemical and physical Chitosan modification for designing enzymatic industrial biocatalysts: How to choose the best strategy?

Taguchi design-assisted co-immobilization of lipase A and B from Candida antarctica onto chitosan: Characterization, kinetic resolution application, and docking studies