Cross-Linked Enzyme Aggregates and Their Application in Enzymatic Pretreatment of Microalgae: Comparison Between CLEAs and Combi-CLEAs

Abstract

Carrier-free immobilization is a key process to develop efficient biocatalysts able to catalyze the cell wall degradation in microalgae where the traditional solid supports cannot penetrate. Thus, the insolubilization of commercial Celluclast®, Alcalase®, and Viscozyme® enzymes by carrier-free immobilization and their application in microalgae pretreatment was investigated. In this study, different precipitants at different ratios (ethanol, acetone, and polyethylene glycol 4000) were tested in the first part of the method, to establish the precipitation conditions. The screening of the best precipitant is needed as it depends on the nature of the enzyme. The best results were studied in terms of immobilization yield, thermal stability, and residual activity and were analyzed using scanning electron microscopy. Moreover, a novel strategy was intended including the three enzymes (combi-CLEAs) to catalyze the enzymatic degradation of Nannochloropsis gaditana microalgal cell wall in one pot. The carrier-free immobilized derivatives were 10 times more stable compared to soluble enzymes under the same. At the best conditions showed its usefulness in the pretreatment of microalgae combined with ultrasounds, facilitating the cell disruption and lipid recovery. The results obtained suggested the powerful application of these robust biocatalysts with great catalytic properties on novel and sustainable biomass such as microalgae to achieve cost-effective and green process to extract valuable bioactive compounds.

Cellulase Immobilization on Nanostructured Supports for Biomass Waste Processing

“…Such cross-linking can be accomplished by a simple interaction with glutaraldehyde [ 75 ] or by more sophisticated methods. Activity of crosslinked enzyme aggregates (CLEA) was found to depend on the precipitant type, which could influence the CLEA density [ 76 , 77 ]. When cross-linked cellulase aggregates prepared by precipitation are combined with magnetic NPs, an extra advantage of easy magnetic manipulation of the nanobiocatalyst is added [ 78 ].…”

Nutraceuticals and Food-Grade Lipid Nanoparticles: From Natural Sources to a Circular Bioeconomy Approach

“…Microalgae have a grow rate 2–3 times higher than that of terrestrial plants, and they are able to accumulate a wide range of bioactive compounds in their cells depending on the microalgae species. Among them, Nannochloropsis gaditana , Isochrysis galbana , Tetraselmis chuii and suecia and Phaedodactylum tricornutum are the main species producing EPA and DHA [ 1 , 3 , 4 , 45 , 46 , 47 , 48 ]. Omega-3 lipids have been proven to be related to the prevention and treatment of some world-recognized diseases, such as cardiometabolic disease and age-related macular degeneration, with promising results [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 49 ].…”

Enzymatic hydrolysis allows an integral valorization of Nannochloropsis oceanica resulting in the production of bioactive peptide extracts and an eicosapentaenoic acid enriched fraction

“…Another alternative is enzymatic hydrolysis, considered more sustainable, cheaper, and simpler, [ 3 ] with different enzymes being studied for Nannochloropsis species. [ 4 ] In addition, enzymatic hydrolysis is one of the main methods for hydrolyzing proteins and releasing bioactive peptides (with several properties already identified, such as anticancer, antimicrobial, antioxidant, and antihypertensive, among others. [ 5 ] ) from several sources, increasing their bioavailability.…”