Effect of metal ions on the enzymatic hydrolysis of hemp seed oil by lipase Candida sp. 99–125

Characterization and Mechanism Study of a Novel Ethanol Acetyltransferase from Hanseniaspora uvarum (EatH) with Good Thermostability, pH Stability, and Broad Alcohol Substrate Specificity

Ethyl acetate, one of the most essential industrial compounds, has a broad range of applications, including flavors, fragrances, pharmaceuticals, cosmetics, and green solvents. Eat1 is accountable for bulk ethyl acetate production in yeasts, yet its properties and molecular mechanism are not well characterized. In this study, an eat1 gene from Hanseniaspora uvarum was obtained through gene mining. EatH showed the highest activity at pH 7.5 and 35 °C and preferred short-chain acyl substrates but had a broad alcohol substrate spectrum from short-chain primary alcohols to aromatic alcohols. Its Km and kcat/Km values toward pNPA were measured to be 1.16 mM and 29.03 L·mmol-1·s-1, respectively. The structure of EatH was composed of a lid domain and a core catalytic domain, with the catalytic triad of Ser124, Asp148, and His296. Additionally, crucial residues and their mechanism were analyzed through molecular docking, site-directed mutagenesis, and molecular dynamics simulation. The mutants N149A, N149K, and N149S showed enhanced enzyme activity toward pNP-hexanoate to 5.0-, 6.6-, and 3.6-fold, and Y204S enhanced enzyme activity for pNP-butyrate by 2.6 times via creating a wider substrate binding pocket and enhancing hydrophobicity. Collectively, this work provided a theoretical basis for the further rational design of EatH and enriched the understanding of the Eat family.

Co2+-boosted catalytic performance of polyhistidine-tagged organophosphate hydrolase locked in cobalt-organic framework

Hydrolysis of organophosphates (OPs) with organophosphate hydrolase (OPH) provides a green approach to degrading OPs, but the success of enzymatic OPs degradation relies on the availability of high-efficiency OPH. Herein, we report a simple but effective way to constructing high-performance OPH preparations based on the in situ encapsulation of hexahistidine-tagged OPH (H6-OPH) into cobaltous zeolitic imidazolate framework (ZIF-67) via biomineralization. ZIF-8 made of the same organic ligand but a different metal ion (Zn2+) was used for comparison. It was found that the H6-tag domain did not affect the catalytic properties of OPH in the absence of Co2+, but boosted the Co2+-activation effect on the H6-OPH catalytic activity by two-fold. Furthermore, H6-OPH@ZIF-67 retained the highly boosted activity, while H6-OPH@ZIF-8 and OPH@ZIF-67/ZIF-8 lost most of the activities. Extensive analysis revealed that the H6-tag promoted the Co2+-induced OPH conformation transition and locked the activated conformation in ZIF-67. Notably, H6-OPH@ZIF-67 not only achieved an activity recovery as high as 348 % and a 321 % increased catalytic efficiency (kcat/Km) over free OPH, but also exhibited greatly improved stability and reusability. The findings underscore the high efficiency of fabricating high-performance OPH preparations via polyhistidine-tag fusion, Co2+ activation and locking by the cobalt-organic framework.

Unveiling the role of mechanical process intensifications and chemical additives in boosting lipase-catalyzed hydrolysis of vegetable oil for fatty acid production: A comprehensive review

The enzymatic production of fatty acids from vegetable oils is becoming a preferred method due to its mild conditions, simplicity, and scalability. This review analyzes studies on enzymatic hydrolysis, exploring various feedstocks, lipases, reaction conditions, and conversion yields. However, a key limitation is the longer reaction time compared to conventional methods. This limitation is primarily due to the immiscibility of triacylglycerols (TAGs) with water at low temperatures and pressures, as well as the lower activity of enzymes compared to chemical catalysts. To overcome these issues, chemical additives are identified as the most effective process intensification strategy. They are easy to implement, cause less damage to lipases, and are more efficient than mechanical methods. The impact of various chemical additives was thoroughly examined for potential improvements in the enzymatic hydrolysis of vegetable oils. A synergistic combination of chemical additives comprising ionic liquids (ILs) and polyols, along with ultrasound, as well as the consideration of immobilization techniques were explored. Overall, this review highlights the potential of chemical additives and their synergistic feasibility in enhancing the enzymatic performance of lipase-catalyzed hydrolysis reactions.

Study of the viability of using lipase-hydrolyzed commercial vegetable oils to produce microbially conjugated linolenic acid-enriched milk

This work studied the viability of using vegetable oils as precursor substrates to develop a dairy product enriched in microbial conjugated linoleic (CLA) and conjugated linolenic (CLNA) acids. Hydrolysis of hempseed, flaxseed (FSO) and soybean (SBO) oils was tested with Candida rugosa (CRL), Pseudomonas fluorescens, or Pancreatic porcine lipases. FSO and SBO, previously hydrolyzed with CRL, were further selected for cow's milk CLA/CLNA-enrichment with Bifidobacterium breve DSM 20091. Thereafter, higher substrate concentrations with hydrolyzed FSO were tested. For all tested oils, CRL revealed the best degrees of hydrolysis (>90 %). Highest microbial CLA/CLNA yield in milk was achieved with hydrolyzed FSO, which led to the appearance of mainly CLNA isomers (0.34 mg/g). At higher substrate concentrations, maximum yield was 0.88 mg/g CLNA. Therefore, it was possible to enrich milk with microbial CLNA using vegetable oil, but not with CLA, nor develop a functional product that can deliver a reliable effective dose.

The evaluation of the performance of rice husk and rice straw as potential matrix to obtain the best lipase immobilized system: creating wealth from wastes

India generates 126.6 and 42 million tons of Rice straw (RS) and Rice husk (RH) annually, respectively. These agro-processing wastes feedstock are dumped in landfills or burnt, releasing toxic gases and particulate matter into the environment. This paper explores the valorization of these wastes feedstock into sustainable, economic products. We compare these wastes as matrices for lipase immobilization. These matrices were characterized, different parameters (pH, temperature, ionic strength, and metal ion cofactors) were checked, and the selected matrix was analyzed for reusability and hydrolysis of vegetable oils. Lipase immobilized Rice straw (LIRS) showed the highest activity with 72.84% protein loading. Field emission scanning electron microscopy (FESEM) demonstrated morphological changes after enzyme immobilization. FTIR showed no new bond formation, and immobilization data was fitted to Freundlich adsorption isotherm (with K = 12.18 mg/g, n_F = 4.5). The highest activity with protein loading, 91.05%, was observed at pH 8, 37 °C temperature, 50 mM ionic strength, and lipase activity doubled in the presence of Mg²⁺ ions. The LIRS retained 75% of its initial activity up to five cycles and efficiently hydrolyzed different oils. The results reflected that the LIRS system performs better and can be used to degrade oily waste.

The optimized biocatalytic synthesis of (S)-methyl 2-chlorobutanoate by Acinetobacter sp. lipase

Epilepsy is a chronic disease caused by sudden abnormal discharge of brain neurons, leading to transient brain dysfunction. Levetiracetam, developed by the UCB company in Belgium, is an effective drug for the treatment of epilepsy. (S)-Methyl 2-chlorobutanoate is an important chiral building block of levetiracetam, which has attracted a great deal of attention. In this study, a strain of lipase-produced Acinetobacter sp. zjutfet-1 was screened from soil samples. At optimized conditions for fermentation and biocatalysis, the bacterial lipase exhibited high catalytic activity for hydrolysis and stereoselectivity toward racemic methyl 2-chlorobutanoate. When the enzymatic reaction was carried out in 6% of racemic substrate, the enantiomeric excess (e.e._s ) reached more than 95%, with a yield of over 86%. Therefore, this lipase can efficiently resolve racemic methyl 2-chlorobutanoate and obtain (S)-methyl 2-chlorobutanoate, which presents great potential in the industrial production of levetiracetam.

Preparation and characterization of a novel thermostable lipase from Thermomicrobium roseum

In this study, a hypothetical lipase gene from Thermomicrobium roseum DSM 5159 (GenBank: ACM04789.1) was recombinantly expressed in two system and characterized.

Study on Lipase-Catalyzed Hydrolysis of Olive Oil at Oil-Water Interface

Olive oil was selected as the oil substrate and hydrolyzed by Candida sp. 99–125 lipase. The hydrolysis rate of olive oil was used as an indicator. Based on the single factor experiment, the effects of dosage of Candida sp. 99–125 lipase, reacting temperature, pH value and water-oil ratio were investigated. Box-Behnken center combination and response surface methodology were utilized to optimize the hydrolysis rate. The results showed that the significant differences of each single factor on lipase hydrolysis of olive oil on the oil-water interface were different. pH value is the first significance factor, and the significance of water oil ratio on lipase hydrolysis of olive oil is second only to pH value. Finally, the mechanism of Candida sp. 99–125 lipase hydrolyzing olive oil at the oil-water interface was discussed.

Chemical, Nutritional and Antioxidant Characteristics of Different Food Seeds

The objective of this study was to determine the chemical composition of five different food seeds (sunflower, poppy, hemp, flax and sesame) regarding fatty acid, mineral (Fe, Cu, Zn, Na, Mg, K, Ca, Al) and protein content. In addition, the total antioxidant capacity of the seeds was evaluated using the photochemiluminescent assay. The food seeds were subjected to lipid extraction and converted into fatty acid methyl esters before the gas chromatography analysis. In all food seeds, the saturated (SFAs), monounsaturated (MUFAs) and polyunsaturated fatty acids (PUFAs) were identified, respectively. PUFAs were the most abundant fatty acids (61.2% ± 0.07% and 84.8% ± 0.08% of total fatty acids), with the highest content in flax and hemp seed oil. Also, high amounts of omega-3 from PUFAs were determined in flax and hempseed oil. Based on the obtained results the sunflower, sesame and poppy seeds are good sources of omega-6, while flax and hemp seeds are good sources of omega-3. All samples are rich in minerals (Na, K, Ca, Mg) and have more than 20% protein content.

Protective effect of β-cyclodextrin on stability of nisin and corresponding interactions involved

Nisin has been extensively employed in food industry as an antimicrobial peptide, but the proteolytic degradation and interference by food components resulted in the decrease of its antimicrobial activity. This study intends to explore the protective effect of β-cyclodextrin (β-CD) on nisin and corresponding interactions involved. The antibacterial experiments indicated that the combination of nisin and β-CD could provide a better antibacterial effect on cooked pork meat. Spectral analysis with UV-vis and fluorescence spectroscopy showed that the micro-environment of nisin could be influenced by β-CD. Tricine-SDS-PAGE results exhibited that the combination of nisin and β-CD could delay the degradation of nisin and improve its stability in the presence of trypsin. In sum, the study provided a potential approach to improve the stability of nisin, especially in the presence of trypsin.