Chitosan coated calcium alginate beads for covalent immobilization of acrylamidase: Process parameters and removal of acrylamide from coffee

Surface enhanced Raman scattering tag enabled ultrasensitive molecular identification of Hippocampus trimaculatus based on DNA barcoding

Rapid and precise DNA barcode-based identification of biological species holds significant potential for pharmaceutical authentication and biomedical diagnostics. Herein, we present a polymerase chain reaction (PCR)-surface-enhanced Raman scattering (SERS) platform that integrates SERS tags for ultrasensitive and fast authentication of Hippocampus trimaculatus, a high-value traditional Chinese medicine (TCM). The SERS tags are composed of gold nanostars, near-infrared cyanine7 Raman reporters and carboxylated polystyrene shells, which achieve single-particle detection sensitivity under 780 nm irradiation. The tags also show excellent colloidal and SERS stability under physiologically relevant conditions (e.g., phosphate buffer saline, serum, 1 mM NaCl, and pH 1-12), with signal variations less than 5 %. The carboxylated polystyrene shells enable efficient DNA functionalization. Leveraging these advancements, the PCR-SERS assay detects genomic DNA (gDNA) at concentrations as low as 10 copies/μL within 20 thermal cycles, with remarkable specificity for Hippocampus trimaculatus over four common adulterant species. Notably, the method reduces amplification requirements to 5 thermal cycles (detection limit of 106 copies/μL) while completing the entire workflow in less than 30 min (conventional qPCR, 20-30 cycles, 1-2 h). Beyond TCM verification, this PCR-SERS platform holds broad applicability for rapid nucleic acid detection in fields ranging from environmental eDNA monitoring to point-of-care diagnostics.

Analysis of acrylamide irradiation degradation effects and products in the starch mechanism

Acrylamide (AA), a neurotoxic and potentially carcinogenic compound, forms in starch-rich foods during high-temperature processing, raising significant food safety concerns. Effective AA mitigation strategies are essential. Among degradation methods, irradiation is a promising food processing technology that reduces harmful contaminants without compromising food quality. To investigate the effect of irradiation on AA degradation and explore potential degradation mechanisms, this study first established a liquid chromatography-based detection method to detect AA in starch matrices. Starch matrices containing AA were irradiated with 60Co-γ rays, and the effects of irradiation dose, initial concentration, and moisture content on degradation efficiency were analyzed. Furthermore, high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS) was employed to identify degradation products and elucidate their formation pathways. Results demonstrated that liquid chromatography effectively detected AA in starch matrices. At an initial AA concentration of 1000 mg/kg and 60 % moisture content, a 2 kGy irradiation dose achieved a 99.12 % degradation rate. Total ion chromatogram analysis identified 17 degradation compounds, with five key products primarily formed through graft polymerization reactions between AA and glucose in the starch matrix. In conclusion, optimized 60Co-γ irradiation effectively degrades AA in starch-based food matrices while generating specific degradation products. These findings offer valuable insights into applying irradiation technology to reduce AA, providing an important reference for enhancing food safety control strategies.

Consortia of Bacillus sp. LY05 and Bacillus cereus LGY06 immobilized on coconut shell charcoal remediates pendimethalin and cadmium contaminated sites in-situ and alleviates peanut's continuous cropping obstacles

The use of artificial addition of microbial consortia into soils is a key strategy to simultaneously alleviate the common contamination and continuous cropping obstacles. This study established the coconut shell charcoal (CSC) LY05 +LGY06 by immobilizing Bacillus sp. LY05 and B. cereus LGY06 on CSC particles, which effectively accelerated the removal of pendimethalin as a possible human carcinogen (91.68 %) and Cd2 + (80.02 %) from the culture-solution, and displayed the prominent re-usability and stability compared with their free coculture consortium. This consortium could detoxify pendimethalin via serial nitro-reduction, oxidation, cyclization, carboxylation and hydroxylation reactions. CSC LY05 +LGY06 could rapidly degrade pendimethalin in sterile (90.01 %) and non-sterile (99.03 %) soils. Moreover, it notably reduced pendimethalin and Cd2+ residuals in pod kernels, pod shells, and plants of peanut growing in continuous cropping soil by 99.19 % and 94.02 %, 99.16 % and 93.94 %, and 98.94 % and 91.85 %, respectively, contrasted to the control. Meanwhile, it significantly promoted the pod yield (>1.28-fold) and quality of continuous cropping peanut by improving the plant agronomic trait, photosynthetic capacity, intracellular water metabolism, nutrient transport capacity, and metabolic activity. This study provides a novel insight into the safe production of agri-products in continuous cropping soils con-contaminated by pesticides and heavy metals.

Immobilized Nucleoside 2'-Deoxyribosyltransferases from Extremophiles for Nucleoside Biocatalysis

The synthesis of nucleosides is crucial for pharmaceutical and biotechnological applications, acting as drugs and as essential building blocks for numerous therapeutic agents. However, most enzymes employed in nucleoside biocatalysis are not recycled, possess limited stability, and have strict substrate selection for ribonucleosides or 2'deoxyribonucleosides. We employed 2'-deoxyribonucleoside transferase (NDT) enzymes from thermophilic and psychrophilic bacteria to demonstrate they can be immobilized to enhance specific activity, stability, and recyclability. NDT enzymes from Chroococcidiopsis thermalis (CtNDT), and Bacillus psychrosaccharolyticus (BpNDT) were immobilized by covalent attachment to chitosan beads. A double mutant of CtNDT, capable of generating 3'deoxyribonucleosides, showed remarkable and increased stability after immobilization compared to the same enzyme in the solution. Furthermore, we demonstrated the recyclability of immobilized biocatalysts, with a 10-fold improvement in reaction yield over 20 consecutive cycles, highlighting the practicality and sustainability of the developed immobilization method. We used our strategy to produce a pharmaceutically relevant 3'deoxyribonucleoside (2-fluoro-3'-deoxyadenosine). This highlights the importance of efficient immobilization techniques to enhance the catalytic properties of NDT enzymes, expanding their utility in biocatalysis.

Microbial amidases: Characterization, advances and biotechnological applications

The amidases (EC 3.5.1.4) are versatile hydrolase biocatalysts that have been the attention of academia and industries for stereo-selective synthesis and bioremediation. These are categorized based on the amino acid sequence and substrate specificity. Notably, the Signature amidase family is distinguished by a characteristic signature sequence, GGSS(S/G)GS, which encompasses highly conserved Ser-Ser-Lys catalytic residues, and the amidases belonging to this family typically demonstrate a broad substrate spectrum activity. The amidases classified within the nitrilase superfamily possess distinct Glu-Lys-Cys catalytic residues and exhibit activity towards small aliphatic substrates. Recent discoveries have underscored the potential role of amidases in the degradation of toxic amides present in polymers, insecticides, and food products. This expands the horizons for amidase-mediated biodegradation of amide-laden pollutants and fosters sustainable development alongside organic synthesis. The burgeoning global production facilities are expected to drive a heightened demand for this enzyme, attributable to its promising chemo-, regio-, and enantioselective hydrolysis capabilities for a variety of amides. Advances in protein engineering have enhanced the catalytic efficiency, structural stability, and substrate selectivity of amidases. Concurrently, the heterologous expression of amidase genes sourced from thermophiles has facilitated the development of highly stable amidases with significant industrial relevance. Beyond their biotransformation capabilities concerning amides, through amido-hydrolase and acyltransferase activities, recent investigations have illuminated the potential of amidase-mediated degradation of amide-containing pollutants in soil and aquatic environments. This review offers a comprehensive overview of recent advancements pertaining to microbial amidases (EC 3.5.1.4), focusing on aspects such as their distribution, gene mining methodologies, enzyme stability, protein engineering, reusability, and biocatalytic efficacy in organic synthesis and biodegradation.

Immobilized chitosan as an efficient adsorbent for columnar adsorption of Cr (VI) from aqueous solution

The current effort focuses on creating an effective adsorbent for Cr (VI) adsorption due to the growing need to address Cr (VI) pollution in aqueous solutions. Chitosan, a biopolymer and polysaccharide with several functional sites, is immobilized on alginate using the ion exchange technique. Both prior to and following Cr (VI) adsorption, the material's shape, crystallinity, and functional groups are reported. Immobilized chitosan was employed to adsorb Cr (VI) in a fixed bed column with variable operational parameters (flow rate, initial chromium content, and bed height). The analysis of breakthrough curves showed that at a flow rate of 10 mL/min, Cr (VI) concentration of 50 mg/L and a bed height of 18 cm, a maximum adsorption of 78.41 % was achieved. The adsorption system and the breakthrough curves were thoroughly understood by using Thomas, Yoon-Nelson and Adams-Bohart kinetic models. There is promise for the large-scale use of synthesized immobilized chitosan because the current adsorption process fits the Thomas and Yoon-Nelson model well and confirms the homogenous bed, low mass transfer resistance, and constant operating conditions throughout the experiment. Furthermore, an exploration of the adsorption mechanism is undertaken and the outcomes are compared with existing literature. The regeneration and reuse tests up to four cycles provided insight into the immobilized chitosan's stability, dependability, and potential for scaling up.

Magnetic nanoparticles-immobilized phospholipase LM and phospholipase 3G: Preparation, characterization, and application on soybean crude oil degumming

Immobilization of enzymes improves their stability and recoverability and is therefore crucial for scientific research and industrial applications. In this study, phospholipase LM (PLLM) and phospholipase 3G (PL3G) were immobilized using Fe3O4@SiO2@CS-COOH polycarboxylated magnetic nanoparticles (MNPs-COOH) as carriers and then used for degumming soybean crude oil. The immobilization rates and relative enzyme activities of these immobilized phospholipases were evaluated to determine the optimal immobilization parameters. The enzyme activities of PLLM-MNPs-COOH and PL3G-MNPs-COOH were 2830.87 and 1162.25 U/g, respectively. Enzymatic properties of the free and immobilized enzymes were compared. Both immobilized phospholipases exhibited higher condition tolerance and stability after immobilization. After 30-day storage at 4 °C, both immobilized phospholipases retained approximately 1.3 times the residual activity of the corresponding free phospholipases. When the degumming conditions were optimized, the residual phosphorus contents of the PLLM-MNPs-COOH- and PL3G-MNPs-COOH-degummed oils were 4.91 and 7.41 mg/kg, respectively, which were consistent with the safety standards for oil products. After 6 cycles, PLLM-MNPs-COOH and PL3G-MNPs-COOH continued to preserve 71.88 % and 70.00 % of their initial activities, respectively. The immobilized phospholipases are thus suitable for degumming soybean crude oil, and the mixed enzymes exhibited better degumming potential.

The Immobilization of a Cyclodipeptide Synthase Enables Biocatalysis for Cyclodipeptide Production

Cyclodipeptide synthases (CDPSs) are enzymes that use aminoacylated tRNAs as substrates to produce cyclic dipeptide natural products acting as anticancer and neuroprotective compounds. Many CDPSs, however, suffer from instability and poor recyclability, while enzyme immobilization can enhance catalyst efficiency and reuse. Here, the CDPS enzyme from Parcubacteria bacterium RAAC4_OD1_1 was immobilized using three different supports: biochar from waste materials, calcium-alginate beads, and chitosan beads. Immobilization of active PbCDPS was successful, and production of the cyclodipeptide cyclo (His-Glu) (cHE) was confirmed by HPLC-MS. Biochar from spent coffee activated with glutaraldehyde, alginate beads, and chitosan beads activated with glutaraldehyde led to a 5-fold improvement in cHE production, with the immobilized enzyme remaining active for seven consecutive cycles. Furthermore, we co-immobilized three enzymes participating in the cascade reaction yielding cHE (PbCDPS, histidyl-tRNA synthetase, and glutamyl-tRNA synthetase). The enzymatic cascade successfully produced the cyclic dipeptide, underscoring the potential of immobilizing various enzymes within a single support. Importantly, we demonstrated that tRNAs remained free in solution and were not adsorbed by the beads. We paved the way for the immobilization of enzymes that utilize tRNAs and other complex substrates, thereby expanding the range of reactions that can be exploited by using this technology.

Enhanced High-Fructose Corn Syrup Production: Immobilizing Serratia marcescens Glucose Isomerase on MOF (Co)-525 Reduces Co2+ Dependency in Glucose Isomerization to Fructose

The escalating demand for processed foods has led to the widespread industrial use of glucose isomerase (GI) for high-fructose corn syrup (HFCS) production. This reliance on GIs necessitates continual Co2+ supplementation to sustain high catalytic activity across multiple reaction cycles. In this study, Serratia marcescens GI (SmGI) was immobilized onto surfaces of the metal-organic framework (MOF) material MOF (Co)-525 to generate MOF (Co)-525-GI for use in catalyzing glucose isomerization to generate fructose. Examination of MOF (Co)-525-GI structural features using scanning electron microscopy-energy dispersive spectroscopy, Fourier-transform infrared spectroscopy, and ultraviolet spectroscopy revealed no structural changes after SmGI immobilization and the addition of Co2+. Notably, MOF (Co)-525-GI exhibited optimal catalytic activity at pH 7.5 and 70 °C, with a maximum reaction rate (Vmax) of 37.24 ± 1.91 μM/min and Km value of 46.25 ± 3.03 mM observed. Remarkably, immobilized SmGI exhibited sustained high catalytic activity over multiple cycles without continuous Co2+ infusion, retaining its molecular structure and 96.38% of its initial activity after six reaction cycles. These results underscore the potential of MOF (Co)-525-GI to serve as a safer and more efficient immobilized enzyme technology compared to traditional GI-based food-processing technologies.

Enzyme-triggered approach to reduce water bodies' contamination using peroxidase-immobilized ZnO/SnO2/alginate nanocomposite

Enzyme immobilization on solid support offers advantages over free enzymes by overcoming characteristic limitations. To synthesize new stable and hyperactive nano-biocatalysts (co-precipitation method), ginger peroxidase (GP) was surface immobilized (adsorption) on ZnO/SnO2 and ZnO/SnO2/SA nanocomposite with immobilization efficacy of 94 % and 99 %, respectively. Thereafter, catalytic and biochemical characteristics of free and immobilized GP were investigated by deploying various techniques, i.e., FTIR, PXRD, SEM, and PL. Diffraction peaks emerged at 2θ values of 26°, 33°, 37°, 51°, 31°, 34°, 36°, 56°, indicating the formation of SnO2 and ZnO. The OH stretching of the H2O molecules was attributed to broad peaks between 3200 and 3500 cm-1, whereas ZnO/SnO2 spikes occurred in the 1626-1637 cm-1 range. SnO stretching mode and ZnO terminal vibrational patterns have been verified at corresponding wavelengths of 625 cm-1 and 560 cm-1. Enzyme entrapment onto substrate was verified via interactions between GP and ZnO/SnO2/SA as corroborated by signals beneath 1100 cm-1. GP-immobilized fractions were optimally active at pH 5, 50 °C, and retained maximum activity after storage of 4 weeks at -4 °C. Kinetic parameters were determined by using a Lineweaver-Burk plot and Vmax for free GP, ZnO/SnO2/GP and ZnO/SnO2/SA/GP with guaiacol as a substrate, were found to be 322.58, 49.01 and 11.45 (μM/min) respectively. A decrease in values of Vmax and KM indicates strong adsorption of peroxidase on support and maximum affinity between nano support and enzyme, respectively. For environmental remediation, free ginger peroxidase (GP), ZnO/SnO2/GP and ZnO/SnO2/SA/GP fractions effectively eradicated highly intricate dye. Multiple scavengers had a significant impact on the depletion of the dye. In conclusion, ZnO/SnO2 and ZnO/SnO2/SA nanostructures comprise an ecologically acceptable and intriguing carrier for enzyme immobilization.

Toxicity, metabolism, and mitigation strategies of acrylamide: a comprehensive review

Acrylamide, a food-borne chemical toxicant, has raised global concern in recent decades. It mainly originated from reducing sugar and free amino acid interactions in the carbohydrate-rich foodstuffs heated at high temperatures. Due to the neurotoxicity and carcinogenicity of AA, the mechanism of formation, toxic effects on health, and mitigation strategies, including conventional approaches and innovative technologies, have been of great interest since its discovery in food. Potato products (especially French fries and crisps), coffee, and cereals(bread and biscuit) are renowned contributors to AA's daily intake. The best preventive methods discussed in the literature include time/temperature optimization, blanching, enzymatic treatment, yeast treatment, additives, pulsed electric fields, ultrasound, vacuum roasting, air frying, and irradiation, exhibiting a high efficacy in AA elimination in food products.

Atrazine Degradation Using Immobilized Triazine Hydrolase from Arthrobacter aurescens TC1 in Mesoporous Silica Nanomaterials

Triazine hydrolase fromArthrobacter aurescens TC1 (TrzN) was successfully immobilized on mesoporous silica nanomaterials (MSNs) for the first time. For both nonfunctionalized MSNs and MSNs functionalized with Zn(II), three pore sizes were evaluated for their ability to immobilize wild-type TrzN: Mobile composition of matter no. 41 (small, 3 nm pores), mesoporous silica nanoparticle material with 10 nm pore diameter (MSN-10) (medium, 6-12 nm pores), and pore-expanded MSN-10 (large, 15-30 nm pores). Of these six TrzN:MSN biomaterials, it was shown that TrzN:MSN-10 was the most active (3.8 ± 0.4 × 10-5 U/mg) toward the hydrolysis of a 50 μM atrazine solution at 25 °C. The TrzN:MSN-10 biomaterial was then coated in chitosan (TrzN:MSN-10:Chit) as chitosan has been shown to increase stability in extreme conditions such as low/high pH, heat shock, and the presence of organic solvents. TrzN:MSN-10:Chit was shown to be a superior TrzN biomaterial to TrzN:MSN-10 as it exhibited higher activity under all storage conditions, in the presence of 20% MeOH, at low and high pH values, and at elevated temperatures up to 80 °C. Finally, the TrzN:MSN-10:Chit biomaterial was shown to be fully active in river water, which establishes it as a functional biomaterial under actual field conditions. A combination of these data indicate that the TrzN:MSN-10:Chit biomaterial exhibited the best overall catalytic profile making it a promising biocatalyst for the bioremediation of atrazine.

Effective mitigation in the amount of acrylamide through enzymatic approaches

Acrylamide (AA), as a food-borne toxicant, is created at some stages of thermal processing in the starchy food through Maillard reaction, fatty food via acrolein route, and proteinous food using free amino acids pathway. Maillard reaction obviously takes place in thermal-based products, being responsible for specific sensory attributes; AA formation, thereby, is unavoidable during the thermal processing. Additionally, AA can naturally occur in soil and water supply. In order to reduce the levels of acrylamide in cooked foods, mitigation techniques can be separated into three different types. Firstly, starting materials low in acrylamide precursors can be used to reduce the acrylamide in the final product. Secondly, process conditions may be modified in order to decrease the amount of acrylamide formation. Thirdly, post-process intervention could be used to reduce acrylamide. Conventional or emerging mitigation techniques might negatively influence the pleasant features of heated foods. The current study summarizes the effect of enzymatic reaction induced by asparaginase, glucose oxidase, acrylamidase, phytase, amylase, and protease to possibly inhibit AA formation or progressively hydrolyze formed AA. Not only enzyme-assisted AA reduction could dramatically maintain bio-active compounds, but also no damaging impact has been reported on the sensorial and rheological properties of the final heated products. The enzyme engineering can be applied to ameliorate enzyme functionality through altering the amino acid sequence like site-specific mutagenesis and directed evolution, chemical modifications by covalent conjugation of L-asparaginase onto soluble/insoluble biocompatible polymers and immobilization. Moreover, it would be possible to improve the enzyme's physical, chemical, and thermal stability, recyclability and prevent enzyme overuse by applying engineered ones. In spite of enzymes' cost-effective and eco-friendly, promoting their large-scale usages for AA reduction in food application and AA bioremediation in wastewater and soil resources.

Bacillus cereus WL08 immobilized on tobacco stem charcoal eliminates butylated hydroxytoluene in soils and alleviates the continuous cropping obstacle of Pinellia ternata

Butylated hydroxytoluene (BHT), as an emerging contaminant in ecosystems, has potential influences on animals, aquatic organisms, and public health, and has been proven to be a major allelochemical of Pinellia ternata. In this study, Bacillus cereus WL08 was used to rapidly degrade BHT in liquid culture. Strain WL08 immobilized on tobacco stem charcoal (TSC) particles notably accelerated BHT removal in contract to its free cells, and exhibited excellent reutilization and storage capacities. The optimal removal parameters of TSC WL08 were ascertained to be pH 7.0, 30 °C, 50 mg L^-1 BHT and 0.14 mg L^-1 TSC WL08. Moreover, TSC WL08 significantly accelerated the degradation of 50 mg L^-1 BHT in sterile and non-sterile soils compared to that of free WL08 or natural dissipation, and notably shortened their half-lives by 2.47- or 362.14- fold, and 2.20- or 14.99- fold, respectively. Simultaneously, TSC WL08 was introduced into the continuous cropping soils of P. ternata, which accelerated the elimination of allelochemical BHT, and notably enhanced the photosynthesis, growth, yield, and quality of P. ternata. This study provides new insights and strategies for the rapid in situ remediation of BHT-polluted soils and effective alleviation of P. ternata cropping obstacles.

Grafting of proteins onto polymeric surfaces: A synthesis and characterization challenge

This review aims at answering the following question: how can a researcher be sure to succeed in grafting a protein onto a polymer surface? Even if protein immobilization on solid supports has been used industrially for a long time, hence enabling natural enzymes to serve as a powerful tool, emergence of new supports such as polymeric surfaces for the development of so-called intelligent materials requires new approaches. In this review, we introduce the challenges in grafting protein on synthetic polymers, mainly because compared to hard surfaces, polymers may be sensitive to various aqueous media, depending on the pH or reductive molecules, or may exhibit state transitions with temperature. Then, the specificity of grafting on synthetic polymers due to difference of chemical functions availability or difference of physical properties are summarized. We present next the various available routes to covalently bond the protein onto the polymeric substrates considering the functional groups coming from the monomers used during polymerization reaction or post-modification of the surfaces. We also focus our review on a major concern of grafting protein, which is avoiding the potential loss of function of the immobilized protein. Meanwhile, this review considers the different methods of characterization used to determine the grafting efficiency but also the behavior of enzymes once grafted. We finally dedicate the last part of this review to industrial application and future prospective, considering the sustainable processes based on green chemistry.

Thermal Contaminants in Coffee Induced by Roasting: A Review

Roasting is responsible for imparting the main characteristics to coffee, but the high temperatures used in the process can lead to the formation of several potentially toxic substances. Among them, polycyclic aromatic hydrocarbons, acrylamide, furan and its derivative compounds, α-dicarbonyls and advanced glycation end products, 4-methylimidazole, and chloropropanols stand out. The objective of this review is to present a current and comprehensive overview of the chemical contaminants formed during coffee roasting, including a discussion of mitigation strategies reported in the literature to decrease the concentration of these toxicants. Although the formation of the contaminants occurs during the roasting step, knowledge of the coffee production chain as a whole is important to understand the main variables that will impact their concentrations in the different coffee products. The precursors and routes of formation are generally different for each contaminant, and the formed concentrations can be quite high for some substances. In addition, the study highlights several mitigation strategies related to decreasing the concentration of precursors, modifying process conditions and eliminating/degrading the formed contaminant. Many of these strategies show promising results, but there are still challenges to be overcome, since little information is available about advantages and disadvantages in relation to aspects such as costs, potential for application on an industrial scale and impacts on sensory properties.

Production and Inhibition of Acrylamide during Coffee Processing: A Literature Review

Coffee is the third-largest beverage with wide-scale production. It is consumed by a large number of people worldwide. However, acrylamide (AA) is produced during coffee processing, which seriously affects its quality and safety. Coffee beans are rich in asparagine and carbohydrates, which are precursors of the Maillard reaction and AA. AA produced during coffee processing increases the risk of damage to the nervous system, immune system, and genetic makeup of humans. Here, we briefly introduce the formation and harmful effects of AA during coffee processing, with a focus on the research progress of technologies to control or reduce AA generation at different processing stages. Our study aims to provide different strategies for inhibiting AA formation during coffee processing and investigate related inhibition mechanisms.

Application of cellulose- and chitosan-based edible coatings for quality and safety of deep-fried foods

Excessive oil uptake and formation of carcinogens, such as acrylamide (AA), heterocyclic amines (HCAs), and polycyclic aromatic hydrocarbons (PAHs), during deep-frying are a potential threat for food quality and safety. Cellulose- and chitosan-based edible coatings have been widely applied to deep-fried foods for reduction of oil uptake because of their barrier property to limit oil ingress, and their apparent inhibition of AA formation. Cellulose- and chitosan-based edible coatings have low negative impacts on sensory attributes of fried foods and are low cost, nontoxic, and nonallergenic. They also show great potential for reducing HCAs and PAHs in fried foods. The incorporation of nanoparticles improves mechanical and barrier properties of cellulose and chitosan coatings, which may also contribute to reducing carcinogens derived from deep-frying. Considering the potential for positive health outcomes, cellulose- and chitosan-based edible coatings could be a valuable method for the food industry to improve the quality and safety of deep-fried foods.

Protease immobilization on a novel activated carrier alginate/dextrose beads: Improved stability and catalytic activity via covalent binding

Protease from Bacillus thuringiensis strain-MA8 was successfully immobilized onto activated Alginate/dextrose (Alg/dex) beads as a new carrier with immobilization yield 77.6 %. The carrier was characterized using Scanning electron microscopy and Fourier transforms infrared spectrophotometer at every step of the immobilization process. Immobilized protease showed an increase of 10 °C in the optimum temperature compared to the free enzyme. However, the optimum pH for both the free and the Alg/dex/protease was found to be 8. The lower activation energy and deactivation rate constant and the higher half-life time and D-value confirm that the new Alg/dex carrier is suitable for promoting enzyme stability. The raise in thermal stability is also shown by the increased deactivation energy of the Alg/dex/protease compared to its free form by 1.47-fold. Likewise, the enzyme immobilization enhancement of Alg/dex/protease was accompanied by a marked increase in enthalpy and Gibbs free energy. The negative entropy for both free and Alg/dex/protease indicates that the enzyme is more stable in thermal deactivation. The Km and Vmax for the Alg/dex/protease were 2.05 and 1.22-times greater than the free form. Furthermore, Alg/dex/protease displayed good reusability as it retained 92.7 and 52.4 % of its activity after 8 and 12 hydrolysis cycles.

Catalytic Biomaterials for Atrazine Degradation

In this paper, triazine hydrolase from Arthrobacter aurescens TC1 (TrzN) was successfully immobilized in alginate beads (TrzN:alginate), alginate beads coated in chitosan (TrzN:chitosan), and tetramethylorthosilicate (TMOS) gels using the sol–gel method (TrzN:sol–gel) for the first time. TrzN:alginate and TrzN:chitosan hydrolyzed 50 µM of atrazine in 6 h with negligible protein loss with an ~80% conversion rate. However, the TrzN:sol–gel biomaterial converted >95% of a 50 µM atrazine solution in an hour with negligible protein loss. The treatment of each of these biomaterials with trypsin confirmed that the catalytic activity was due to the encapsulated enzyme and not surface-bound TrzN. All three of the biomaterials showed potential for long-term storage and reuse, with the only limitation arising from the loss of protein in the storage buffer for the TrzN:alginate and TrzN:chitosan biomaterials, not the denaturation of the encapsulated TrzN. TrzN:sol–gel stood out, with ~100% activity being retained after 10 consecutive reactions. Additionally, the materials stayed active in methanol concentrations <10%, suggesting the ability to increase the solubility of atrazine with organic solvents. The structural integrity of the TrzN:alginate and TrzN:chitosan materials became limiting in extreme pH conditions, while TrzN:sol–gel outperformed WT TrzN. Overall, the TrzN:sol–gel biomaterial proved to be the best atrazine dichlorination biocatalyst. As sol–gels can be cast into any desired shape, including pellets, which can be used in columns, the TrzN:sol–gel biomaterial provides a new avenue for the design of bioremediation methodologies for the removal of atrazine from the environment.

Co-Immobilization of D-Amino Acid Oxidase, Catalase, and Transketolase for One-Pot, Two-Step Synthesis of L-Erythrulose

Here, we present an immobilized enzyme cascade in a basket-type reactor allowing a one-pot, two-step enzymatic synthesis of L-erythrulose from D-serine and glycolaldehyde. Three enzymes, D-amino acid oxidase from Rhodotorula gracilis (DAAORg), catalase from bovine liver (CAT), and transketolase from Geobacillus stearothermophilus (TKgst) were covalently immobilized on silica monolithic pellets, characterized by an open structure of interconnected macropores and a specific surface area of up to 300 m2/g. Three strategies were considered: (i) separate immobilization of enzymes on silica supports ([DAAO][CAT][TK]), (ii) co-immobilization of two of the three enzymes followed by the third ([DAAO+CAT][TK]), and (iii) co-immobilization of all three enzymes ([DAAO+CAT+TK]). The highest L-erythrulose concentrations were observed for the co-immobilization protocols (ii) and (iii) (30.7 mM and 29.1 mM, respectively). The reusability study showed that the best combination was [DAAO + CAT][TK], which led to the same level of L-erythrulose formation after two reuse cycles. The described process paves the way for the effective synthesis of a wide range of α-hydroxyketones from D-serine and suitable aldehydes.

Polymer/Enzyme Composite Materials—Versatile Catalysts with Multiple Applications

A significant interest was granted lately to enzymes, which are versatile catalysts characterized by natural origin, with high specificity and selectivity for particular substrates. Additionally, some enzymes are involved in the production of high-valuable products, such as antibiotics, while others are known for their ability to transform emerging contaminates, such as dyes and pesticides, to simpler molecules with a lower environmental impact. Nevertheless, the use of enzymes in industrial applications is limited by their reduced stability in extreme conditions and by their difficult recovery and reusability. Rationally, enzyme immobilization on organic or inorganic matrices proved to be one of the most successful innovative approaches to increase the stability of enzymatic catalysts. By the immobilization of enzymes on support materials, composite biocatalysts are obtained that pose an improved stability, preserving the enzymatic activity and some of the support material’s properties. Of high interest are the polymer/enzyme composites, which are obtained by the chemical or physical attachment of enzymes on polymer matrices. This review highlights some of the latest findings in the field of polymer/enzyme composites, classified according to the morphology of the resulting materials, following their most important applications.

Microfluidic fabrication of tunable alginate-based microfibers for the stable immobilization of enzymes

Immobilized enzymes have drawn extensive attention due to their enhanced stability, easy separation from reaction mixture, and prominent recyclability. Nevertheless, it is still an ongoing challenge to develop potent immobilization techniques which are capable of stable enzyme encapsulation, minimal loss of activity, and modulability for various enzymes and applications. Here, microfibers with tunable size and composition were fabricated using a home-made microfluidic device. These microfibers were able to efficiently encapsulate bovine serum albumin (BSA), glucose oxidase (GOx), and horseradish peroxidase (HRP). But the physically adsorbed enzymes readily diffused into the catalytic reaction system. The leakage of enzymes could be substantially inhibited by conjugating to polyacrylic acid (PAA) and incorporating into alginate-based microfibers, enabling stable immobilization, improved recyclability, and enhanced thermostability. In addition, GOx and HRP-loaded microfibers were fabricated under the optimized conditions for the visual detection of glucose using the cascade reaction of these enzymes, showing sensitive color change to glucose with concentration range of 0-2 mM. Due to the tunability and versatility, this microfluidic-based microfiber platform may provide a valuable approach to the enzyme immobilization for the cascade catalysis and diagnoses with multiple clinical markers. This article is protected by copyright. All rights reserved.

Mechano-chemical and biological energetics of immobilized enzymes onto functionalized polymers and their applications

Enzymes of commercial importance, such as lipase, amylase, laccase, phytase, carbonic anhydrase, pectinase, maltase, glucose oxidase etc., show multifunctional features and have been extensively used in several fields including fine chemicals, environmental, pharmaceutical, cosmetics, energy, food industry, agriculture and nutraceutical etc. The deployment of biocatalyst in harsh industrial conditions has some limitations, such as poor stability. These drawbacks can be overcome by immobilizing the enzyme in order to boost the operational stability, catalytic activity along with facilitating the reuse of biocatalyst. Nowadays, functionalized polymers and composites have gained increasing attention as an innovative material for immobilizing the industrially important enzyme. The different types of polymeric materials and composites are pectin, agarose, cellulose, nanofibers, gelatin, and chitosan. The functionalization of these materials enhances the loading capacity of the enzyme by providing more functional groups to the polymeric material and hence enhancing the enzyme immobilization efficiency. However, appropriate coordination among the functionalized polymeric materials and enzymes of interest plays an important role in producing emerging biocatalysts with improved properties. The optimal coordination at a biological, physical, and chemical level is requisite to develop an industrial biocatalyst. Bio-catalysis has become vital aspect in pharmaceutical and chemical industries for synthesis of value-added chemicals. The present review describes the current advances in enzyme immobilization on functionalized polymers and composites. Furthermore, the applications of immobilized enzymes in various sectors including bioremediation, biosensor and biodiesel are also discussed.

Molecular imprinting technology and poly (ionic liquid)s: Promising tools with industrial application for the removal of acrylamide and furanic compounds from coffee and other foods

Coffee is one of the most consumed beverages in the world. Coffee provides to the consumer special sensorial characteristics, can help to prevent diseases, improves physical performance and increases focus. In contrast, coffee consumption supplies a significant source of substances with carcinogenic and genotoxic potential such as furan, hydroxymethylfurfural (HMF), furfural (F), and acrylamide (AA). The present review addresses the issues around the presence of such toxic substances formed in Maillard reaction (MR) during thermal treatments in food processing, from chemical and, toxicological perspectives, occurrences in coffee and other foods processed by heating. In addition, current strategies advantages and disadvantages are presented along with application of molecular imprinting technology (MIT) and poly (ionic liquid) s (PIL) as an alternative to reduce the furan, HMF, F and AA content in coffee and other foods.

Facile synthesis of pH-responsive sodium alginate/carboxymethyl chitosan hydrogel beads promoted by hydrogen bond

In this work, a novel synthesis strategy of sodium alginate/carboxymethyl chitosan hydrogel beads promoted by hydrogen bond was described. The beads were prepared by dropping the blends of two polymers into the citric acid solution. Besides hydrogen bonding, electrostatic interactions were also involved in the formation of the hydrogel beads. The thermal stability experiments revealed that the more the content of carboxymethyl chitosan, the better the thermal stability of the beads. The beads exhibited excellent pH sensitivity, pH reversibility, and lactoferrin loading capacity. The swelling ratio of the bead and its protein releasing profile was pH-dependent, which could prevent premature protein release in the gastric environment. Also, the circular dichroism results demonstrated that lactoferrin could maintain its structure during the loading and releasing process. The obtained results revealed that the hydrogel beads prepared in this work could be used as a potential protein carrier for oral delivery.

Removal of difenoconazole and nitenpyram by composite calcium alginate beads during apple juice clarification

A novel genipin crosslinked calcium alginate/chitosan/polydopamine composite beads (g-Alg/CS/PDA) was synthesized for the removal of residual difenoconazole and nitenpyram during the clarification of apple juice. The composite beads with low potential health risks for all of the main materials were natural, green and biocompatible. Since g-Alg/CS/PDA can both clarify and adsorb, pesticide residues could be removed during the clarification of juice without additional steps. The g-Alg/CS/PDA beads were characterized, and the adsorption parameters, including the pesticide residue levels, adsorption time, pH, ionic strength, fructose concentration and adsorbent dose, were optimized. The adsorption data were fitted to the Freundlich isotherm model (R² = 0.9604, 0.9625) and the pseudo-second-order kinetic model (R² = 0.9993, 0.9999). The results indicated that the adsorption behavior of beads was heterogeneous. Moreover, the rate was controlled by several factors. The adsorption mechanism of two pesticides was also discussed. Hydrophobic and π-π conjugation interactions played a dominant role for the adsorption of difenoconazole, while hydrogen bonding and electrostatic interactions were the main factors for nitenpyram.

Synchronous degradation of phenol and aniline by Rhodococcus sp.strain PB-1entrapped in sodium alginate-bamboo charcoal-chitosan beads

The biodegradation of benzene series compounds is a difficult problem in environment pollution control, which is attributed to the deficiency of high efficiency bacteria and suitable embedding materials. In this study, the immobilized cells Rhodococcussp. strain PB-1 was used to synchronously biodegrade phenol and aniline by entrapped in sodium alginate (SA)-bamboo charcoal (BC)-chitosan acetate (CA) beads. The free cells of the strain PB-1 could completely degrade 1500 mg/L phenol or 800 mg/L aniline within 48 h, while the degradation rate of 2000 mg/L phenol and 1500 mg/L aniline was 35.76% and 68.06% at 72 h, respectively. The ortho-cleavage pathway was used to degrade phenol and aniline by strain PB-1. However, after entrapped with SA-BC-CA beads,the removal rate of 2000 mg/L phenol was 100% at 108 h, 1500 mg/L aniline was 100% at 62 h and 2000-3000 mg/L total toxic compounds was over 95% at 120 h. These beads could be used four times and were more effective than SA or SA-BC beads. The SA-BC-CA beads could remarkably improve the stability and degradation efficiency of strain PB-1, and thus provide a potential application in the removal of phenol and aniline in wastewater.

Three-Dimensional Chiral Supramolecular Microenvironment Strategy for Enhanced Biocatalysis

How the three-dimensional (3D) chiral environment affects the biocatalysis remains an important issue, thereby inspiring the development of a microenvironment that highly mimics the natural features of enzyme to guarantee enhanced biocatalysis. In this study, two gelators bearing d/l-phenylalanine as chiral centers are designed to construct the 3D chiral catalytic microenvironment for enhancing the biocatalysis of lipase. Such a microenvironment is programmed through chiral transmission of chirality from molecular chirality to achiral polymers. It shows that the chirality of the microenvironment evidently influences the catalytic efficiency of immobilized lipase inside the system, and the 3D microenvironment constructed by right-handed helical nanostructures can enhance the catalytic activity of lipase inside as high as 10-fold for catalyzing 4-nitrophenyl palmitate (NPP) to 4-nitrophenol (NP) and 1.4-fold for catalyzing lipids to triglycerides (TGs) in 3T3-L1 cells than that of the achiral microenvironment. Moreover, the 3D chiral microenvironment has the merits of good catalytic efficiency, high storage stability, and efficient recyclability. This strategy of designing a 3D chiral microenvironment suitable for biocatalysis will overcome the present limitations of enzymatic immobilization in traditional materials and enhance the understanding of biocatalysis.

Synergistic effect of the activated carbon addition from leather wastes in chitosan/alginate-based composites

In this work, chitosan/alginate composites were developed by the gelation method with the addition of different amounts of activated carbon produced from tannery waste (ACTW). The performance of these composites was verified through the adsorption of the textile dye Remazol Brilliant Blue R (RBBR). A synergistic effect was observed by the addition of ACTW; with a specific surface area up to 45.584 m²/g, the maximum adsorption capacity was 300.96 mg/g. The synergy was due to the reduction in steric hindrance, with the adsorption capacity 1.2 times higher than expected. The material was regenerated with sodium hydroxide for 10 cycles. The composite containing 30% ACTW (AC30) was applied in the treatment of real textile effluent, with 30% reductions in the biochemical oxygen demand (BOD), 39% in the chemical oxygen demand (COD), 78% in turbidity, and 67% in color.

Biological removal of deltamethrin in contaminated water, soils and vegetables by Stenotrophomonas maltophilia XQ08

The consideration of ecological and human health risk is an emerging concern with the excessive or inappropriate use of deltamethrin. In this study, the degradation conditions of the newly deltamethrin-degrading strain Stenotrophomonas maltophilia XQ08 were optimized, which were temperature 35 °C, pH 7.5, cell concentration 5.5 × 10⁸ cfu/mL, and substrate concentration 50 mg/L. Strain XQ08 could effectively degrade deltamethrin into three smaller molecular weight and lower toxic compounds. Enriched strain XQ08 was immobilized in a charcoal-alginate matrix and possessed more prominent biodegradability, reusability, storability and thermostability than free XQ08. In a continuous reactor system, immobilized XQ08 could averagely remove 78.81% of deltamethrin at the gradient influent dosages of 50, 75 and 100 mg/L within 30 d. Immobilized XQ08 introduced into the filed brown and yellow soils exhibited a superior degradation potential for deltamethrin with the half-lives of 1.77 and 2.04 d, which were 2.39 and 2.14 folds, or 6.09 and 5.47 folds faster than free XQ08 degradation (4.23 and 4.37 d) or natural dissipation (10.78 and 11.16 d), respectively. Moreover, application of free XQ08 decreased the persistence of deltamethrin in Brassica pekinensis and Brassica chinensis from 5.47 and 6.23 to 2.05 and 2.32 d, or by 62.52% and 62.76%, respectively. This study provides a feasible, effective and rapid biological removal technology for deltamethrin-contaminated environments in situ.

Magnetic Cross-Linked Enzyme Aggregates of a Transpeptidase-Specialized Variant (N450D) of Bacillus licheniformis γ-Glutamyl Transpeptidase: An Efficient and Stable Biocatalyst for l-Theanine Synthesis

γ-Glutamyl transpeptidase (GGT) catalyzes the transfer of glutathione’s γ-glutamyl group and related γ-glutamyl amides to water, amino acids or peptides, and utilizes a conserved Thr residue to process its own polypeptide chain into a large and a small subunit that then assemble to produce a catalytically competent enzyme. In this study, the magnetic cross-linked enzyme aggregates (mCLEAs) of a transpeptidase-specialized variant (N450D) of Bacillus licheniformis GGT were successfully prepared with optimized process parameters viz.1.25:1 (v/v) of isopropanol to N450D (0.3 mg/mL) ratio/0.02:1 (w/w) of enzyme to 3-aminopropyl triethoxysilane (APTES)-coated magnetic nanoparticle ratio/20 mM of glutaraldehyde. The prepared magnetic nanoparticles and immobilized enzyme (N450D-mCLEAs) were characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy, field-emission scanning electron microscope integrated with energy dispersive X-ray spectroscopy (FESEM/EDS), and superparamagnetic analysis. As compared with free enzyme, N450D-mCLEAs displayed significantly higher heat resistance at temperatures of 55 and 60 °C, and had a greater stability over a storage period of one month. The immobilized enzyme could also be reused for 10 consecutive biocatalytic cycles with no significant reduction in the percent yield of l-theanine. Conclusively, this immobilization strategy surely provides a meaningful glance of developing N450D-mediated biocatalysis for the production of physiologically important γ-glutamyl compounds.

Development and microbiological evaluation of chitosan and chitosan-alginate microspheres for vaginal administration of metronidazole

Metronidazole is the drug of choice in the treatment of bacterial vaginosis, but the oral therapy can induce several collateral effects. Aim of this work was the development of a vaginal multiparticulate system, loaded with metronidazole, able to improve its residence time allowing a complete drug release. Several kinds of MS were prepared using chitosan dissolved in different organic acids or alginate coated with chitosan. FTIR and DSC analyses were performed to study the interactions between the drug and the polymers, while MS morphology was investigated with optical and electron microscopy. All the formulations were characterized in terms of drug entrapment efficiency, mucoadhesion, swelling capacity and drug release behavior, demonstrating the best results for alginate MS coated with chitosan. The formulations evidenced a complete and rapid release of drug, compared with the commercial form: Zidoval®.The best formulations assayed for antibacterial activity confirmed the suitability of this new formulation for the vaginal treatment of local diseases.

Enhancement of dicarboximide fungicide degradation by two bacterial cocultures of Providencia stuartii JD and Brevundimonas naejangsanensis J3

Bioremediation is commonly conducted by microbial consortia rather than individual species in natural environments. Biodegradation of dicarboximide fungicides in brunisolic soil were significantly enhanced by two bacterial cocultures of Providencia stuartii JD and Brevundimonas naejangsanensis J3. The cocultures degraded 98.42 %, 95.44 %, and 96.81 % of 50 mg/L dimethachlon, iprodione, and procymidone in liquid culture within 6 d respectively, whose efficiency was 1.23 and 1.26, 1.25 and 1.23, and 1.24 and 1.24 times of strains JD and J3, respectively. The cocultures could effectively degrade dimethachlon, iprodione and procymidone to simple products. Moreover, the cocultures immobilized in a charcoal-alginate-chitosan carrier obviously surpassed free cocultures in terms of degradability, stability and reusability. In the field brunisolic soils treated by immobilized cocultures, 96.74 % of 20.25 kg a.i./ha dimethachlon, 95.02 % of 7.50 kg a.i./ha iprodione and 96.27 % of 7.50 kg a.i./ha procymidone were degraded after 7 d, respectively. Moreover, the lower half-lifes (1.53, 1.59 and 1.57 d) by immobilized cocultures were observed, as compared to free cocultures (3.60, 4.03 and 3.92 d) and natural dissipation (21.33, 20.51 and 20.09 d). This study highlights that strains JD and J3 have significant synergetic degradation advantages in rapid bioremediation of dicarboximide fungicide contamination sites.

Optimization of Cellulase Immobilization with Sodium Alginate-Polyethylene for Enhancement of Enzymatic Hydrolysis of Microcrystalline Cellulose Using Response Surface Methodology

A novel method of immobilizing cellulase on sodium alginate (SA)-polyethylene glycol (PEG) enabled the cellulase to be used repeatedly. The matrix of the immobilized cellulase was detected and characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. In comparison with SA-immobilized cellulase, the relative enzyme activity and immobilization rate increased by 25% and 18%, respectively. The application range of the immobilized enzyme in terms of temperature and pH was larger than that of the free enzyme, and its thermal stability increased. The immobilized enzyme was used in enzymatic hydrolysis, in which MCC was used as the substrate. The optimal conditions for enzymatic hydrolysis were as follows: the dosage of SA-PEG-immobilized cellulase was 3.55 g/g total solids of the substrate, the concentration of the substrate was 13.16%, and the pH was 5.11. In comparison with the yield of reducing sugars in the first round of hydrolysis of MCC by SA-immobilized cellulase, the yield in the hydrolysis of MCC by SA-PEG-immobilized cellulase increased by 133%. After five cycles of repeated use, the total yield of reducing sugars when MCC was hydrolyzed by SA-PEG-immobilized cellulase was similar to that achieved with free cellulase. In comparison with the free enzyme, the highest yield when the immobilized enzyme was used was 22.68%. Therefore, the immobilized cellulase exhibited high performance in enzymatic hydrolysis.

High internal phase Pickering emulsions stabilized by dialdehyde amylopectin/chitosan complex nanoparticles

High internal phase Pickering emulsions (HIPPEs) have attracted intensive interest for their great potential in foods, cosmetics, and biomedical applications. However, the relatively poor biodegradability and biocompatibility of inorganic and synthetic particulate emulsifiers greatly limit their practical applications. Here, a kind of biobased nanoparticles, namely dialdehyde amylopectin/chitosan complex nanoparticles (DAPCNPs), were fabricated by Schiff base reaction between dialdehyde amylopectin and chitosan with the assistance of ultrasonication treatment. The resultant DAPCNPs were employed to stabilize O/W HIPPEs with various oils, such as toluene, cyclohexane, styrene and edible rapeseed oil. Moreover, the resultant DAPCNPs-stabilized HIPPEs showed high stability under various environmental stresses (80 °C; 20 mM and 100 mM aqueous NaCl solutions). Furthermore, porous scaffolds were also fabricated by freeze-drying cyclohexane-in-water HIPPEs stabilized by DAPCNPs after the introduction of polyvinyl alcohol (PVA) into the continuous phase. These findings would give inspiration for designing polysaccharides-based nanoparticles to stabilize HIPPEs and improve their practical applications.

Functional Application of Sulfur-Containing Spice Compounds

Sulfur-containing spice compounds possess diverse biological functions and play an important role in food, chemicals, pharmaceuticals, and agriculture. The development of functional spices has become increasingly popular, especially for medicinal functions for dietary health. Thus, this review focuses on the properties and functions of sulfur-containing spice compounds, including antioxidant, anti-inflammatory, antiobesity, anticancer, antibacterial, and insecticidal functions, among others. Developments over the last five years concerning the properties of sulfur-containing spice compounds are summarized and discussed.

A comprehensive review on incredible renewable carriers as promising platforms for enzyme immobilization & thereof strategies

Enzymes are the highly versatile bio-catalysts having the potential for being employed in biotechnological and industrial sectors to catalyze biosynthetic reactions over a commercial point of view. Immobilization of enzymes has improved catalytic properties, retention activities, thermal and storage stabilities as well as reusabilities of enzymes in synthetic environments that have enthralled significant attention over the past few years. Dreadful efforts have been emphasized on the renewable and synthetic supports/composite materials to reserve their inherent characteristics such as biocompatibility, non-toxicity, accessibility of numerous reactive sites for profitable immobilization of biological molecules that often serve diverse applications in the pharmaceutical, environmental, and energy sectors. Supports should be endowed with unique physicochemical properties including high specific surface area, hydrophobicity, hydrophilicity, enantioselectivities, multivalent functionalization which professed them as competent carriers for enzyme immobilization. Organic, inorganic, and nano-based platforms are more potent, stable, highly recovered even after used for continuous catalytic processes, broadly renders the enzymes to get efficiently immobilized to develop an inherent bio-catalytic system that displays higher activities as compared to free-counter parts. This review highlights the recent advances or developments on renewable and synthetic matrices that are utilized for the immobilization of enzymes to deliver emerging applications around the globe.

Rapid degradation of dimethomorph in polluted water and soil by Bacillus cereus WL08 immobilized on bamboo charcoal-sodium alginate

The presence of hazardous dimethomorph residues in the environment poses a threat to birds, aquatic organisms and mammals. The novel pure strain Bacillus cereus WL08 responsible for detoxifying dimethomorph was isolated from dimethomorph-polluted soils. The immobilized system of WL08 was developed using bamboo charcoal (BC) and sodium alginate (SA). Immobilization significantly improved tolerance and stability of strain WL08. Under optimal conditions of pH 7.0 and 30 ℃, free and immobilized WL08 degraded 66.95% and 96.88% of 50 mg/L dimethomorph within 72 h, respectively. Moreover, strain WL08 effectively degraded dimethomorph to simple products which were lower toxic than dimethomorph. In a continuous reactor system, immobilized WL08 removed 85.61% of dimethomorph for 30 d at an influent concentration of 50-100 mg/L. In the field soil sprayed with 4.20 kg a.i./ha 80% dimethomorph water dispersible granule (WDG) was treated by immobilized WL08, the lower half-life (1.93 d) was observed, as compared with free WL08 (4.28 d) and natural dissipation (23.82 d). Immobilized WL08 can be considered as a tool for the removal of dimethomorph in water-soil systems. This study provides a feasible microbe-based strategy for bioremediation of dimethomorph-polluted environments.