Biochemical characterization of highly organic solvent-tolerant cutinase from Fusarium oxysporum

Advances in microbial exoenzymes bioengineering for improvement of bioplastics degradation

Plastic pollution has become a major global concern, posing numerous challenges for the environment and wildlife. Most conventional ways of plastics degradation are inefficient and cause great damage to ecosystems. The development of biodegradable plastics offers a promising solution for waste management. These plastics are designed to break down under various conditions, opening up new possibilities to mitigate the negative impact of traditional plastics. Microbes, including bacteria and fungi, play a crucial role in the degradation of bioplastics by producing and secreting extracellular enzymes, such as cutinase, lipases, and proteases. However, these microbial enzymes are sensitive to extreme environmental conditions, such as temperature and acidity, affecting their functions and stability. To address these challenges, scientists have employed protein engineering and immobilization techniques to enhance enzyme stability and predict protein structures. Strategies such as improving enzyme and substrate interaction, increasing enzyme thermostability, reinforcing the bonding between the active site of the enzyme and substrate, and refining enzyme activity are being utilized to boost enzyme immobilization and functionality. Recently, bioengineering through gene cloning and expression in potential microorganisms, has revolutionized the biodegradation of bioplastics. This review aimed to discuss the most recent protein engineering strategies for modifying bioplastic-degrading enzymes in terms of stability and functionality, including enzyme thermostability enhancement, reinforcing the substrate binding to the enzyme active site, refining with other enzymes, and improvement of enzyme surface and substrate action. Additionally, discovered bioplastic-degrading exoenzymes by metagenomics techniques were emphasized.

Functional characterization and structural insights of three cutinases from the ascomycete Fusarium verticillioides

Cutinases are serine esterases that belong to the α/β hydrolases superfamily. The natural substrates for these enzymes are cutin and suberin, components of the plant cuticle, the first barrier in the defense system against pathogen invasion. It is well-reported that plant pathogens produce cutinases to facilitate infection. Fusarium verticillioides, one important corn pathogens, is an ascomycete upon which its cutinases are poorly explored. Consequently, the objective of this study was to perform the biochemical characterization of three precursor cutinases (FvCut1, FvCut2, and FvCut3) from F. verticillioides and to obtain structural insights about them. The cutinases were produced in Escherichia coli and purified. FvCut1, FvCut2, and FvCut3 presented optimal temperatures of 20, 40, and 35 °C, and optimal pH of 9, 7, and 8, respectively. Some chemicals stimulated the enzymatic activity. The kinetic parameters revealed that FvCut1 has higher catalytic efficiency (Kcat/Km) in the p-nitrophenyl-butyrate (p-NPB) substrate. Nevertheless, the enzymes were not able to hydrolyze polyethylene terephthalate (PET). Furthermore, the three-dimensional models of these enzymes showed structural differences among them, mainly FvCut1, which presented a narrower opening cleft to access the catalytic site. Therefore, our study contributes to exploring the diversity of fungal cutinases and their potential biotechnological applications.

Cutinase production from Fusarium verticillioides using response surface methodology and its application as potential insecticide degrader

Cutinase, a multifunctional enzyme, has shown great potential in environmental applications such as degradation of plastics and some commonly used insecticides. To overcome these environmental threatening problems, attempts should be made to enhance enzyme production. In the present study, a cutinolytic fungus was isolated from the soil. Based on 18 s rDNA sequencing, it was found that isolate AR08 belongs to the genus Fusarium and clades with Fusarium verticillioides. Optimization of medium composition for enhancement in cutinase production was done using. classical and statistical methods. Firstly, key factors were selected by one variable at a time (OVAT) method, then by Plackett- Burman design. Concentration of these important factors was optimized by Central Composite design. A total of 30 experiments were conducted and the optimized concentration of sodium nitrate, dipotassium hydrogen phosphate, flaxseed oil and zinc sulphate were found to be 0.455%, 0.305%, 2% and 0.0355% respectively. The result of ANOVA (analysis of variance) test revealed that p value was significant for the model. Interaction between flaxseed oil and sodium nitrate was found to have a positive effect on cutinase production. A 14.57 fold increase in enzyme activity was found under optimized conditions with the maximum cutinase activity of 626.6 IUml-1.

Characteristics of a recombinant Fusarium verticillioides cutinase and its effects on enzymatic hydrolysis of rice straw

The current study heterologously expressed a cutinase from Fusarium verticillioides by Pichia pastoris and investigated its properties and effects on the hydrolysis of rice straw. The optimal pH and temperature for F. verticillioides cutinase were 8.0 and 50 °C, respectively. F. verticillioides cutinase had poor thermal stability and could be inhibited by some metal ions, inhibitors, and detergents (5 mM), including Ni²⁺, Zn²⁺, Cu²⁺, Ca²⁺, Mn²⁺, sodium dodecyl sulfate, EDTA, and Tween-20. F. verticillioides cutinase could tolerate 15% methanol and dimethyl sulfoxide but was significantly repressed by 15% ethanol and acetone with 48% and 63% residual activity, respectively. F. verticillioides cutinase could degrade the cuticle of rice straw with palmitic acid and stearic acid as the main products. However, the dissolving sugars released from the rice straw treated with F. verticillioides cutinase were significantly reduced by 29.2 μg/mL compared with the control (107.9 μg/mL). Similarly, the reducing sugars produced from the cellulase hydrolysis of rice straw pretreated with F. verticillioides cutinase were reduced by 63.5 μg/mL relative to the control (253.6 μg/mL). Scanning electron microscopy results showed that numerous tuberculate or warty protrusions were present nearly everywhere on the surface of rice straw treated with F. verticillioides cutinase, and some protrusions even covered and blocked the stomata of the rice straw surface. Current limited data indicate that F. verticillioides cutinase might not be an appropriate choice for improving the utilization of agricultural straws.

Lipase catalyzed interesterification of Amazonian patauá oil and palm stearin for preparation of specific-structured oils

This study showed that enzymatic interesterification of Amazonian oils could be an important tool in order to produce new oils with physicochemical properties that improve the applications of these raw materials. Structured oils of Amazonian patauá oil and palm stearin using two lipases were produced in three different enzymatic systems: first, a crude lipase from the fungus Rhizopus sp (a microorganism isolated in our laboratory); second, a commercial lipase; and third, to check any synergistic effect, a mixture of both lipases (Rhizopus sp and commercial). The lipase from Rhizopus sp was specific in the incorporation of oleic acid at the sn-1,3 positions of the triacylglycerol, resulting in an oil richer in saturated fatty acid in the sn-2 position. This enzyme, produced by solid-state fermentation, even though crude, was fatty acid and positional specific and able to operate at low concentration (2.5 %, w/w). In the second enzyme system, the commercial lipase from Thermomyces lanuginosus was not specific in the tested conditions; there was no change in the distribution of saturated and unsaturated fatty acids in the three positions of the triacylglycerol profile, there was only a replacement by the type of fatty acid at the same position. In the third enzyme system, the mixture of both lipases shows no synergic effect. The structured oils retained the concentration of bioactive α- and γ- tocopherol in the three enzyme systems. Triacylglycerol classes and Thermal behavior tests indicated the formation of more homogeneous triacylglycerols, especially the mono and di-unsaturated.

Characterization of an acidic cold-adapted cutinase from Thielavia terrestris and its application in flavor ester synthesis

An acidic cutinase (TtcutB) from Thielavia terrestris CAU709 was purified to apparent homogeneity with 983 Um g(-1) specific activity. The molecular mass of the enzyme was estimated to be 27.3 and 27.9 kDa by SDS-PAGE and gel filtration, respectively. A peptide sequence homology search revealed no homologous cutinases from T. terrestris, except for one putative cutinase gene (XP003656017.1), indicating that TtcutB is a novel enzyme. TtcutB exhibited an acidic pH optimum of 4.0, and stability at pH 2.5-10.5. Optimal activity was at 55 °C, it was stable up to 65 °C, and retained over 30% activity at 0 °C. Km values toward p-nitrophenyl (pNP) acetate, pNP-butyrate and pNP-caproate were 8.3, 1.1 and 0.88 mM, respectively. The cutinase exhibited strong synthetic activity on flavor ester butyl butyrate under non-aqueous environment, and the highest esterification efficiency of 95% was observed under the optimized reaction conditions. The enzyme's unique biochemical properties suggest great potential in flavor esters-producing industries.

Organic solvent tolerant lipases and applications

Lipases are a group of enzymes naturally endowed with the property of performing reactions in aqueous as well as organic solvents. The esterification reactions using lipase(s) could be performed in water-restricted organic media as organic solvent(s) not only improve(s) the solubility of substrate and reactant in reaction mixture but also permit(s) the reaction in the reverse direction, and often it is easy to recover the product in organic phase in two-phase equilibrium systems. The use of organic solvent tolerant lipase in organic media has exhibited many advantages: increased activity and stability, regiospecificity and stereoselectivity, higher solubility of substrate, ease of products recovery, and ability to shift the reaction equilibrium toward synthetic direction. Therefore the search for organic solvent tolerant enzymes has been an extensive area of research. A variety of fatty acid esters are now being produced commercially using immobilized lipase in nonaqueous solvents. This review describes the organic tolerance and industrial application of lipases. The main emphasis is to study the nature of organic solvent tolerant lipases. Also, the potential industrial applications that make lipases the biocatalysts of choice for the present and future have been presented.