Synthesis of fructooligosaccharides from Aspergillus niger commercial inulinase immobilized in montmorillonite pretreated in pressurized propane and LPG

Activity and stability of lipase from Candida Antarctica after treatment in pressurized fluids

Lipase B from Candida antarctica (CalB) is one of the biocatalysts most used in organic synthesis due to its ability to act in several medium, wide substrate specificity and enantioselectivity, tolerance to non-aqueous environment, and resistance to thermal deactivation. Thus, the objective of this work was to treat CalB in supercritical carbon dioxide (SC-CO₂) and liquefied petroleum gas (LPG), and measure its activity before and after high-pressure treatment. Residual specific hydrolytic activities of 132% and 142% were observed when CalB was exposed to SC-CO₂ at 35 ℃, 75 bar and 1 h and to LPG at 65 ℃, 30 bar and 1 h, respectively. Residual activity of the enzyme treated at high pressure was still above 100% until the 20th day of storage at low temperatures. There was no difference on the residual activity loss of CalB treated with LPG and stored at different temperatures over time. Greater difference was observed between CalB treated with CO₂ and flash-frozen in liquid nitrogen (- 196 ℃) followed by storage in freezer (- 10 ℃) and CalB stored in freezer at - 10 ℃. Such findings encourage deeper studies on CalB as well as other enzymes behavior under different types of pressurized fluids aiming at industrial application.

Oligosaccharides production from coprophilous fungi: An emerging functional food with potential health-promoting properties

Functional foods are essential food products that possess health-promoting properties for the treatment of infectious diseases. In addition, they provide energy and nutrients, which are required for growth and survival. They occur as prebiotics or dietary supplements, including oligosaccharides, processed foods, and herbal products. However, oligosaccharides are more efficiently recognized and utilized, as they play a fundamental role as functional ingredients with great potential to improve health in comparison to other dietary supplements. They are low molecular weight carbohydrates with a low degree of polymerization. They occur as fructooligosaccharide (FOS), inulooligosaccharadie (IOS), and xylooligosaccahride (XOS), depending on their monosaccharide units. Oligosaccharides are produced by acid or chemical hydrolysis. However, this technique is liable to several drawbacks, including inulin precipitation, high processing temperature, low yields, and high production costs. As a consequence, the application of microbial enzymes for oligosaccharide production is recognized as a promising strategy. Microbial enzymatic production of FOS and IOS occurs by submerged or solid-state fermentation in the presence of suitable substrates (sucrose, inulin) and catalyzed by fructosyltransferases and inulinases. Incorporation of FOS and IOS enriches the rheological and physiological characteristics of foods. They are used as low cariogenic sugar substitutes, suitable for diabetics, and as prebiotics, probiotics and nutraceutical compounds. In addition, these oligosaccharides are employed as anticancer, antioxidant agents and aid in mineral absorption, lipid metabolism, immune regulation etc. This review, therefore, focuses on the occurrence, physico-chemical characteristics, and microbial enzymatic synthesis of FOS and IOS from coprophilous fungi. In addition, the potential health benefits of these oligosaccharides were discussed in detail.

Inulinase from Rhodotorula mucilaginosa: immobilization and application in the production of fructooligosaccharides

The crude extract containing inulinase from Rhodotorula mucilaginosa was obtained by submerged fermentation. Inulinase was immobilized on chicken eggshell by physical adsorption and covalent crosslinking, using glutaraldehyde as a crosslinking reagent, and Celite by adsorption. Fructooligosaccharides production was performed using immobilized inulinase (5%, w/v) and inulin substrate solution under experimental conditions evaluated through Doehlert experimental design. The production of inulinase was optimized for concentrations of D-glucose and yeast extract at 12.5 and 0.5 g/L, respectively, resulting in an optimal activity of 0.62 U. The optimal pH and temperature for enzyme activity were 8.0 and 75 °C, respectively, leading to an optimal activity of 3.54 U. The highest immobilization efficiency (46.27%) was obtained upon immobilization on Celite. Immobilization by adsorption to eggshell allowed for specific activity of 4.15 U/g, and adsorption to Celite resulted in specific activity of 3.70 U/g. The highest titer in fructooligosaccharides was obtained with an initial inulin concentration of 250 g/L (25%, w/v), and a reaction time of 16 h. Hence, immobilized inulinase proved to be a promising catalyst for fructooligosaccharides production since the formulation is performed through a simple, low-cost, and large-scale applicable methodology.

Efficient fructose production from plant extracts by immobilized inulinases from Kluyveromyces marxianus and Helianthus tuberosus

The enzymatic hydrolysis of poly- and oligosaccharides from plants seems like an advantageous approach for sugars production. Two inulinases producing fructose from plant oligosaccharides were isolated from yeast Kluyveromyces marxianus and plant Helianthus tuberosus. Both enzymes were immobilized on polymeric carriers by using the static adsorption approach. We could save 80.4% of the initial catalytic activity of plant inulinase immobilized on KU-2 cation-exchange resin and 75.5% of yeast enzyme activity adsorbed on AV-17-2P anion-exchange resin. After immobilization, the Km values increased 1.5 and 6 times for enzymes from K. marxianus and H. tuberosus, respectively. The optimal temperatures for catalysis of both enzymes were increased from 48-50 °C up to 70 °C. The activities of both immobilized enzymes remained unchanged after the 10 cycles of 20-min hydrolysis reaction at 70 °C model batch reactor. Sorbents, native and immobilized enzymes did not exhibit any mutagenic or cytotoxic activity.

Optimization of simultaneously enzymatic fructo- and inulo-oligosaccharide production using co-substrates of sucrose and inulin from Jerusalem artichoke

Prebiotic substances are extracted from various plant materials or enzymatic hydrolysis of different substrates. The production of fructo-oligosaccharide (FOS) and inulo-oligosaccharide (IOS) was performed by applying two substrates, sucrose and inulin; oligosaccharide yields were maximized using central composite design to evaluate the parameters influencing oligosaccharide production. Inulin from Jerusalem artichoke (5-15% w/v), sucrose (50-70% w/v), and inulinase from Aspergillus niger (2-7 U/g) were used as variable parameters for optimization. Based on our results, the application of sucrose and inulin as co-substrates for oligosaccharide production through inulinase hydrolysis and synthesis is viable in comparative to a method using a single substrate. Maximum yields (674.82 mg/g substrate) were obtained with 5.95% of inulin, 59.87% of sucrose, and 5.68 U/g of inulinase, with an incubation period of 9 hr. The use of sucrose and inulin as co-substrates in the reaction simultaneously produced FOS and IOS from sucrose and inulin. Total conversion yield was approximately 67%. Our results support the high value-added production of oligosaccharides using Jerusalem artichoke, which is generally used as a substrate in prebiotics and/or bioethanol production.

X-Ray Crystallography as a Tool to Determine Three-Dimensional Structures of Commercial Enzymes Subjected to Treatment in Pressurized Fluids

The study of enzyme function often involves a multi-disciplinary approach. Several techniques are documented in the literature towards determining secondary and tertiary structures of enzymes, and X-ray crystallography is the most explored technique for obtaining three-dimensional structures of proteins. Knowledge of three-dimensional structures is essential to understand reaction mechanisms at the atomic level. Additionally, structures can be used to modulate or improve functional activity of enzymes by the production of small molecules that act as substrates/cofactors or by engineering selected mutants with enhanced biological activity. This paper presentes a short overview on how to streamline sample preparation for crystallographic studies of treated enzymes. We additionally revise recent developments on the effects of pressurized fluid treatment on activity and stability of commercial enzymes. Future directions and perspectives on the the role of crystallography as a tool to access the molecular mechanisms underlying enzymatic activity modulation upon treatment in pressurized fluids are also addressed.

Microbial enzymatic production and applications of short-chain fructooligosaccharides and inulooligosaccharides: recent advances and current perspectives

The industrial production of short-chain fructooligosaccharides (FOS) and inulooligosaccharides is expanding rapidly due to the pharmaceutical importance of these compounds. These compounds, concisely termed prebiotics, have biofunctional properties and hence health benefits if consumed in recommended dosages. Prebiotics can be produced enzymatically from sucrose elongation or via enzymatic hydrolysis of inulin by exoinulinases and endoinulinases acting alone or synergistically. Exoinulinases cleave the non-reducing β-(2, 1) end of inulin-releasing fructose while endoinulinases act on the internal linkages randomly to release inulotrioses (F3), inulotetraoses (F4) and inulopentaoses (F5) as major products. Fructosyltransferases act by cleaving a sucrose molecule and then transferring the liberated fructose molecule to an acceptor molecule such as sucrose or another oligosaccharide to elongate the short-chain fructooligosaccharide. The FOS produced by the action of fructosyltransferases are 1-kestose (GF2), nystose (GF3) and fructofuranosyl nystose (GF4). The production of high yields of oligosaccharides of specific chain length from simple raw materials such as inulin and sucrose is a technical challenge. This paper critically explores recent research trends in the production and application of short-chain oligosaccharides. Inulin and enzyme sources for the production of prebiotics are discussed. The mechanism of FOS chain elongation and also the health benefits associated with prebiotics consumption are discussed in detail.