A comprehensive review on preparation, structure-activities relationship, and calcium bioavailability of casein phosphopeptides.

Calcium is one of the important elements for human health. Calcium deficiencies can lead to numerous diseases. Calcium chelating peptides have shown potential application in the management of calcium deficiencies. Casein phosphopeptides (CPP) are phosphoseryl-containing fragments of casein by enzymatic hydrolysis or fermentation during manufacture of milk products as well as during intestinal digestion. An increasing number of CPP with the ability to facilitate and enhance the bioavailability of calcium are being discovered and identified. In this review, 249 reported CPP derived from four types of bovine casein (αs1, αs2, ß and κ) were collected, and the amino acid sequence and phosphoserine group information were sorted out. This review outlines the current enzyme hydrolysis, detection methods, purification, structure-activity relationship and mechanism of intestinal calcium absorption in vitro and in vivo as well as application of CPP.

Enhancing the activity and thermal stability of a phthalate-degrading hydrolase by random mutagenesis.

Our previous work has reported that EstJ6 was a phthalate-degrading hydrolase. In the study, a random mutant library was constructed by two rounds of error-prone PCR, three mutants (ET1.1, ET2.1, and ET2.2) with enhanced hydrolytic activity against dibutyl phthalate (DBP) were obtained. The best mutant ET2.2, accumulated three amino acid substitutions (Thr91Met, Ala67Val, and Val249Ile) and exhibited 2.8-fold increase enzyme activity and 2.3-fold higher expression level. Meanwhile, compared with EstJ6, ET2.2 showed over 50% improvement in thermostability (at 50 °C for 1 h) and 1.2-fold increase in 50% methanol tolerance. Kinetic parameters analysis revealed that the Km value for ET2.2 decreased by 60% and the kcat/Km value increased by 166%. The molecular docking indicated that the shortening of hydrogen bond between Ser146-OH and DBP-CO, which may led to an increase in enzyme activity and catalytic efficiency, the enhancement of hydrophobicity of hydrophobic pocket was related to the improvement of organic solvents tolerance, and three hydrophobic amino acid substitutions Thr91Met, Ala67Val, and Val249Ile facilitated to improve the thermal stability and organic solvents tolerance. These results confirmed that random mutagenesis was an effective tool for improving enzyme properties and lay a foundation for practical applications of phthalate-degrading hydrolase in biotechnology and industrial fields.

Identification and Determination of Seven Phenolic Acids in Brazilian Green Propolis by UPLC-ESI-QTOF-MS and HPLC.

Brazilian green propolis is a complex mixture of natural compounds that is difficult to analyze and standardize; as a result, controlling its quality is challenging. In this study, we used the positive and negative modes of ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time of flight mass spectrometry in conjunction with high-performance liquid chromatography for the identification and characterization of seven phenolic acid compounds in Brazilian green propolis. The optimal operating conditions for the electrospray ionization source were capillary voltage of 3500 V and drying and sheath gas temperatures of 320 °C and 350 °C, respectively. Drying and sheath gas flows were set to 8 L/min and 11 L/min, respectively. Brazilian green propolis was separated using the HPLC method, with chromatograms for samples and standards measured at 310 nm. UPLC-ESI-QTOF-MS was used to identify the following phenolic compounds: Chlorogenic acid, caffeic acid, isochlorogenic acid A, isochlorogenic acid B, isochlorogenic acid C, caffeic acid phenethyl ester (CAPE), and artepillin C. Using a methodologically validated HPLC method, the seven identified phenolic acids were then quantified among different Brazilian green propolis. Results indicated that there were no significant differences in the content of a given phenolic acid across different Brazilian green propolis samples, owing to the same plant resin sources for each sample. Isochlorogenic acid B had the lowest content (0.08 ± 0.04) across all tested Brazilian green propolis samples, while the artepillin C levels were the highest (2.48 ± 0.94). The total phenolic acid content across Brazilian green propolis samples ranged from 2.14-9.32%. Notably, artepillin C quantification is an important factor in determining the quality index of Brazilian green propolis; importantly, it has potential as a chemical marker for the development of better quality control methods for Brazilian green propolis.

Women's employment trajectories during early adulthood in urban China: A cohort comparison.

This study uses retrospective work history data from CGSS 2008 and employs group-based trajectory analysis to model the diverse employment trajectories of cohorts of urban Chinese women (born in the 1940s-1970s) during young adulthood (age 20-35). We identify ideal-types of urban women's employment trajectories and explore traits associated with each group type. In particular, we examine whether and how the timing of marriage and fertility as well as socioeconomic background help to distinguish patterns of women's labor force attachment in young adulthood. We also examine how these patterns change across cohorts given China's rapid social transformations in the past few decades. We find that delaying family formation is generally associated with more consistent work attachment, but this relationship is also largely associated with one's socioeconomic background. Our results reveal significant cohort variations in the shape of women's employment trajectories and we discuss how institutional and cultural contexts of different historical periods could have shaped family formation and employment processes differently. Our findings highlight the heterogeneity of urban women's work and family formation patterns in the context of rising gender inequalities and rapid socioeconomic transformation over time.

Characterization of a novel amidohydrolase with promiscuous esterase activity from a soil metagenomic library and its application in degradation of amide herbicides.

Amide herbicides have been extensively used worldwide and have received substantial attention due to their adverse environmental effects. Here, a novel amidohydrolase gene was identified from a soil metagenomic library using diethyl terephthalate (DET) as a screening substrate. The recombinant enzyme, AmiH52, was heterologously expressed in Escherichia coli and later purified and characterized, with the highest activity occurring at 40 ℃ and pH 8.0. AmiH52 was demonstrated to have both esterase and amidohydrolase activities, which exhibited highly specific activity for p-nitrophenyl butyrate (2669 U/mg) and degrading activity against several amide herbicides. In particular, it displayed the strongest activity against propanil, with a high degradation rate of 84% at 8 h. A GC-MS analysis revealed that propanil was transformed into 3,4-dichloroaniline (3,4-DCA) during this degradation. The molecular interactions and binding stability were then analyzed by molecular docking and molecular dynamics simulation, which revealed that several key amino acid residues, including Tyr164, Trp66, Ala59, Val283, Arg58, His33, His191, and His226, are involved in the specific interactions with propanil. This study provides a function-driven screening method for amide herbicide hydrolase from the metagenomic libraries and a promising propanil-degrading enzyme (AmiH52) for potential applications in environmental remediation.

Compressive Behaviors of Thin-Walled Steel Tube Stub Columns Filled with Self-Compacting Concrete Containing Recycled Aggregate.

Natural resources have been excessively consumed, and large amounts of construction wastes have been generated, owing to the fast development of civil industry, causing crucial environmental issues. Therefore, reusable construction waste fabricated into recycled concrete offers a good strategy to solve this issue. Thus, this article first develops thin-walled steel tubes stub columns filled with self-compacting concrete containing recycled coarse aggregate. Afterwards, the compressive behaviors of the columns when undergoing axial compression loading to failure are explored. Subsequently, the effect of types of self-compacting concrete and wall thickness on failure modes and the relationships between load and displacement/strain is discussed comprehensively. Moreover, models of load-displacement/strain behaviors are proposed. The results show that columns with identical wall thicknesses containing both natural and recycled coarse aggregate display similar failure modes, mainly presenting as local buckling and rupture. The shape of the load-displacement/strain curves for identical wall thicknesses are almost the same. Nevertheless, the maximum load and stiffness of columns containing recycled coarse aggregate are lower than those of columns containing natural coarse aggregate. Additionally, the maximum loads corresponding to wall thickness of 1.2 mm and 3.0 mm are decreased by 18.4% and 5.8%, respectively. Moreover, the proposed models can reasonably evaluate the relationships between load and displacement/strain. This paper demonstrates that thin-walled steel tubular columns containing recycled coarse aggregate present positive compressive behaviors and thus exhibit great potential for developing environmentally friendly and sustainable civil infrastructures.

Eccentric Compression Behaviors of Self-Compacting Concrete-Filled Thin-Walled Steel Tube Columns.

For the sake of solving sustainability issues and analyzing the complicated service force states, eccentric compression experiments on self-compacting concrete-filled thin-walled medium-length steel tube columns with a circular cross-section were carried out in the present study. Thereafter, the influence of the eccentric ratios and the wall thickness factors on the mechanical behavior and failure characteristics of both the eccentrically loaded and axially loaded columns was comprehensively analyzed. Finally, prediction formulas for the ultimate load of the columns under eccentric compression were proposed, and a comprehensive comparison of the ultimate loads between the predicted values and experimental values was also conducted. The results indicated that the typical failure characteristics of the eccentrically loaded columns presented lateral deflection together with buckling, while the axially compressed columns displayed expansion and rupture at local positions. Moreover, the ultimate loads of the eccentrically loaded columns decreased by 43.0% and 34.5% in comparison to the columns under axial compression, with the wall thickness factor decreasing from 116.7 to 46.7, respectively. Meanwhile, the ratios of the ultimate loads calculated using design codes to the tested values were in the range of 0.70~0.90, which demonstrated that the design codes could predict the ultimate loads conservatively. Additionally, the ratios of the ultimate loads calculated using the proposed formulas to the tested values were within the range of 0.99~1.08, implying that the proposed formulas were more accurate than the design codes. At the same time, the initial stiffness of the columns under eccentric compression was correspondingly lower than that of the columns undergoing axial compression. The lateral deflections along the height of the columns were almost symmetrical at different loading levels. This study could provide a meaningful approach for designing columns and facilitate their application in civil industry.

Engineering Modular and Highly Sensitive Cell-Based Biosensors for Aromatic Contaminant Monitoring and High-Throughput Enzyme Screening.

Although a variety of whole-cell-based biosensors have been developed for different applications in recent years, most cannot meet practical requirements due to insufficient sensing performance. Here, we constructed two sets of modular genetic circuits by serial and parallel modes capable of significantly amplifying the input/output signal in Escherichia coli. The biosensors are engineered using σ54-dependent phenol-responsive regulator DmpR as a sensor and enhanced green fluorescent protein as a reporter. Cells harboring serial and parallel genetic circuits displayed nearly 9- and 16-fold higher sensitivity than the general circuit. The genetic circuits enabled rapid detection of six phenolic contaminants in 12 h and showed the low limit of detection of 2.5 and 2.2 ppb for benzopyrene (BaP) and tetracycline (Tet), with a broad detection range of 0.01-1 and 0.005-5 µM, respectively. Furthermore, the positive rate was as high as 73% when the biosensor was applied to screen intracellular enzymes with ester-hydrolysis activity from soil metagenomic libraries using phenyl acetate as a phenolic substrate. Several novel enzymes were isolated, identified, and biochemically characterized, including serine peptidases and alkaline phosphatase family protein/metalloenzyme. Consequently, this study provides a new signal amplification method for cell-based biosensors that can be widely applied to environmental contaminant assessment and screening of intracellular enzymes.

Improving the activity and expression level of a phthalate-degrading enzyme by a combination of mutagenesis strategies and strong promoter replacement.

Phthalic acid esters (PAEs) are widely used plasticizers found in consumer products, which enter the environment and pose severe threats to human health. Here, a new PAE-degrading enzyme EstJ6 was modified by combining mutagenesis strategies and a strong promoter replacement to improve its catalytic activity and expression level. Four mutants with enhanced activity were obtained by random mutation, among which EstJ6M1.1 exhibited the highest catalytic activity with an increase in catalytic activity by 2.9-fold toward dibutyl phthalate (DBP) than that of the wild-type (WT) enzyme. With these mutants as a template, a variant EstJ6M2 with 3.1-fold higher catalytic activity and 4.61 times higher catalytic efficiency (Kcat/Km) was identified by staggered extension PCR. Targeting four mutation sites of EstJ6M2, a variant EstJ6M3.1 was gained by site-directed saturation mutagenesis and displayed 4.3-fold higher activity and 5.97 times higher Kcat/Km than WT. The expression level of three mutants EstJ6M1.1, EstJ6M2, and EstJ6M3.1, as well as the WT, increased nearly threefold after a strong promoter replacement. These results provide a proof-theoretical basis and practicable pipeline for applying PAE-degrading enzymes.

BON domain-containing protein-mediated co-selection of antibiotic and heavy metal resistance in bacteria.

The widespread antibiotic resistance of bacteria has become one of the most severe threats to public health. However, the mechanisms that allow microbial acquisition of resistance are still poorly understood. In the present study, a novel BON domain-containing protein was heterologously expressed in Escherichia coli. It functions as an efflux pump-like to confer resistance to various antibiotics, especially for ceftazidime, with a >32-fold increase in minimum inhibitory concentration (MIC). The fluorescence spectroscopy experiment indicated that BON protein could interact with several metal ions, such as copper and silver, which has been associated with the induced co-regulation of antibiotic and heavy metal resistance in bacteria. Furthermore, the BON protein was demonstrated to spontaneously self-assemble into a trimer and generate a central pore-like architecture for antibiotic transporting. A WXG motif as a molecular switch is essential for forming the transmembrane oligomeric pores and controls the interaction between BON protein and cell membrane. Based on these findings, a mechanism termed "one-in, one-out", was proposed for the first time. The present study provides new insights into the structure and function of BON protein and a previously unidentified antibiotic resistance mechanism, filling the knowledge gap in understanding BON protein-mediated intrinsic antibiotic resistance.

Enhancing the Hydrolysis and Acyl Transfer Activity of Carboxylesterase DLFae4 by a Combinational Mutagenesis and In-Silico Method.

In the present study, a feruloyl esterase DLFae4 identified in our previous research was modified by error-prone PCR and site-directed saturation mutation to enhance the catalytic efficiency and acyltransferase activity further. Five mutants with 6.9-118.9% enhanced catalytic activity toward methyl ferulate (MFA) were characterized under the optimum conditions. Double variant DLFae4-m5 exhibited the highest hydrolytic activity (270.97 U/mg), the Km value decreased by 83.91%, and the Kcat/Km value increased by 6.08-fold toward MFA. Molecular docking indicated that a complex hydrogen bond network in DLFae4-m5 was formed, with four of five bond lengths being shortened compared with DLFae4, which might account for the increase in catalytic activity. Acyl transfer activity assay revealed that the activity of DLFae4 was as high as 1550.796 U/mg and enhanced by 375.49% (5823.172 U/mg) toward 4-nitrophenyl acetate when residue Ala-341 was mutated to glycine (A341G), and the corresponding acyl transfer efficiency was increased by 7.7 times, representing the highest acyltransferase activity to date, and demonstrating that the WGG motif was pivotal for the acyltransferase activity in family VIII carboxylesterases. Further experiments indicated that DLFae4 and variant DLFae4 (A341G) could acylate cyanidin-3-O-glucoside effectively in aqueous solution. Taken together, our study suggested the effectiveness of error-prone PCR and site-directed saturation mutation to increase the specific activity of enzymes and may facilitate the practical application of this critical feruloyl esterase.

Research on the Regulation of Plipastatin Production by the Quorum-Sensing ComQXPA System of Bacillus amyloliquefaciens.

Plipastatin is a cyclic lipopeptide synthesized by non-ribosomal peptide synthetases (NRPS), which has a diverse range of applications in postharvest preservation of fruits and vegetables, biological control, and feed processing. Whereas the yield of plipastatin in wild Bacillus sp. is low, its chemical structure is complex and challenging to synthesize, significantly limiting its production and application. ComQXPA-PsrfA, a quorum-sensing (QS) circuit from Bacillus amyloliquefaciens, was constructed in this study. Two QS promoters MuPsrfA and MtPsrfA, with 35 and 100% increased activity, respectively, were obtained by mutating the original promoter PsrfA. Thus, the natural promoter of plipastatin was replaced by a QS promoter to achieve the dynamic regulation of plipastatin, which increased the yield of plipastatin by 3.5 times. Integrating ComQXPA into plipastatin mono-producing M-24:MtPsrfA increased the yield of plipastatin to 3850 mg/L, representing the highest yield reported to date. Four new plipastatins were identified via UPLC-ESI-MS/MS and GC-MS analysis of fermentation products of mono-producing engineered strains. Among them, three plipastatins contained two double bonds in the fatty acid side chain, representing the first example of a new type of plipastatin. Our results indicate that the QS system ComQXPA-PsrfA of Bacillus can dynamically regulate plipastatin production, and the pipeline could be extended to the other strains to regulate target products dynamically.

Influence of temperature gradient of slab track on the dynamic responses of the train-CRTS III slab track on subgrade nonlinear coupled system.

Temperature is an important load for ballastless track. However, there is little research on the system dynamic responses when a train travels on a ballastless track under the temperature gradient of ballastless track. Considering the moving train, temperature gradient of slab track, gravity of slab track, and the contact nonlinearity between interfaces of slab track, a dynamic model for a high-speed train runs along the CRTS III slab track on subgrade is developed by a nonlinear coupled way in ANSYS. The system dynamic responses under the temperature gradient of slab track with different amplitudes are theoretically investigated with the model. The results show that: (1) The proportions of the initial force and stress caused by the temperature gradient of slab track are different for different calculation items. The initial fastener tension force and positive slab bending stress have large proportions exceeding 50%. (2) The maximum dynamic responses for slab track are not uniform along the track. The maximum slab bending stress, slab acceleration, concrete base acceleration appear in the slab middle, at the slab end, and at the concrete base end, respectively. (3) The maximum accelerations of track components appear when the fifth or sixth wheel passes the measuring point, and at least two cars should be used. (4) The temperature gradient of slab track has a small influence on the car body acceleration. However, the influences on the slab acceleration, concrete base acceleration, fastener tension force are large, and the influence on the slab bending stress is huge.

Improving Degradation of Polycyclic Aromatic Hydrocarbons by Bacillus atrophaeus Laccase Fused with Vitreoscilla Hemoglobin and a Novel Strong Promoter Replacement.

Laccases catalyze a variety of electron-rich substrates by reducing O2 to H2O, with O2 playing a vital role as the final electron acceptor in the reaction process. In the present study, a laccase gene, lach5, was identified from Bacillus atrophaeus through sequence-based screening. LacH5 was engineered for modification by fusion expression and promoter replacement. Results showed that the purified enzyme LacH5 exhibited strong oxidative activity towards 2,2'-azinobis(3-ehtylbenzothiazolin-6-sulfnic acid) ammonium salt (ABTS) under optimum pH and temperature conditions (pH 5.0, 60 °C) and displayed remarkable thermostability. The activity of the two fusion enzymes was enhanced significantly from 14.2 U/mg (LacH5) to 22.5 U/mg (LacH5-vgb) and 18.6 U/mg (Vgb-lacH5) toward ABTS after LacH5 fusing with Vitreoscilla hemoglobin (VHb). Three of six tested polycyclic aromatic hydrocarbons (PAHs) were significantly oxidized by two fusion laccases as compared with LacH5. More importantly, the expression level of LacH5 and fusion protein LacH5-vgb was augmented by 3.7-fold and 7.0-fold, respectively, by using a novel strong promoter replacement. The results from the current investigation provide new insights and strategies for improving the activity and expression level of bacterial laccases, and these strategies can be extended to other laccases and multicopper oxidases.

Promoting the Calcium-Uptake Bioactivity of Casein Phosphopeptides in vitro and in vivo.

Casein phosphopeptides have been studied widely for their ability to chelate calcium. However, systematic studies on the effects of casein phosphopeptides (CPP) on calcium absorption in vitro and in vivo are scarce. The purities of two commercially available products, CPP1 and CPP2, are 18.37 and 25.12%, respectively. Here, the in vitro calcium binding capacity of CPP2 was 142.56 ± 7.39 mg/g, which was higher than that of CPP1 (107.15 ± 6.27 mg/g). The calcium transport results in a Caco-2 monolayer model indicated that, relative to controls, CPP1 and CPP2 increased calcium transport by 21.78 and 53.68%, respectively. Subsequent animal experiments showed that the CPP2-Ca-H group (1% Ca, 0.4% CPP2) had significant increases in the femur index, serum Ca2+ and serum osteocalcin levels, and femoral Ca content. The CPP2-Ca-H animal also had decreased serum alkaline phosphatase levels, parathyroid hormone content, and urinary pyridinoline content. Overall, our results demonstrated that CPP2 had stronger effects on promoting calcium uptake than CPP1.

Characterization of a novel carboxylesterase with catalytic activity toward di(2-ethylhexyl) phthalate from a soil metagenomic library.

A novel carboxylesterase gene estyz5 was isolated from a soil metagenomic library. The recombinant enzyme EstYZ5 is 298 amino acids in length with a predicted molecular weight of 32 kDa. Sequence alignment and phylogenetic analysis revealed that EstYZ5 belongs to the hormone-sensitive lipase (HSL) family with a deduced catalytic triad of Ser144-Glu238-His268. EstYZ5 contains two conserved motifs, a pentapeptide motif GDSAG and a HGGG motif, which are typically found in members of the HSL family. Esterolytic activity of the recombinant enzyme was optimal at 30 °C and pH 8.0, and the kcat/Km value of the enzyme for the optimum substrate p-nitrophenyl butyrate was as high as 1272 mM-1·s-1. Importantly, EstYZ5 showed activity toward di(2-ethylhexyl) phthalate with complex side chains, which is rare for HSLs. Molecular docking simulations revealed that the catalytic triad and an oxyanion hole likely play vital roles in enzymatic activity and specificity. The phthalate-degrading activity of EstYZ5, combined with its high levels of esterolytic activity, render this new enzyme a candidate for biotechnological applications.

Extraction, isolation, characterization and antimicrobial activities of non-extractable polyphenols from pomegranate peel.

Non-extractable polyphenols (NEPPs) in pomegranate peel were released by acid hydrolysis followed by extraction using ethyl acetate (EtOAc). Ten NEPPs were identified in the hydrolysate using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Six compounds were then isolated from the EtOAc extracts whose structures were identified as ß-sitosterol-3-O-glycoside (1), ß-sitosterol (2), ursolic acid (3), corosolic acid (4), asiatic acid (5) and arjunolic acid (6) using a wide range of spectroscopic analyses. Compounds 4-6 were isolated for the first time from pomegranate peel. Antimicrobial experiments revealed that compound 3 and 5 showed significant antimicrobial activity against a range of pathogens, particularly compound 5 which exhibited selective inhibitive activity towards Staphylococcus aureus with a minimum inhibitory concentration (MIC) of 16 µg/ml. The present study has provided new insights into the composition of bound chemicals in pomegranate peel and laid a foundation for improving its further processing and utilization.

A comparative study between Chinese propolis and Brazilian green propolis: metabolite profile and bioactivity.

Among different types, Chinese propolis (ChPs) and Brazilian green propolis (BrGPs) have been shown to contain multi-functional properties. Despite extensive research in the field, reports comparing propolis from different geographical areas are still limited, compromising our current understanding of the potential therapeutic effect associated with propolis and its derived compounds. Herein, a comparative study between ChPs and BrGPs including their metabolite profile and bioactivities was performed. Interestingly, even when ChPs and BrGPs showed similar anti-inflammatory potential, our results showed that they contained very different levels of ethanol extract, total flavonoids and total phenolic acids and in fact, LC-MS metabolic profiling and pattern recognition could effectively distinguish ChPs and BrGPs. Moreover, all the propolis samples tested showed good anti-oxidant activity and no significant difference of free radical scavenging capacity existed between ChPs and BrGPs. In conclusion, ChPs and BrGPs have a distinct chemome, but their antioxidant and anti-inflammatory activities are similar.

Deciphering calcium-binding behaviors of casein phosphopeptides by experimental approaches and molecular simulation.

Casein phosphopeptides (CPPs) as premium additives in functional foods can facilitate the transport and adsorption of calcium. The atomic resolution decipherment of calcium-CPP binding behaviors is critical for understanding the calcium bioavailability enhancement potential of CPPs. In the present study, the experimental methods (UV-vis, FTIR and isothermal titration calorimetry) and molecular dynamics simulation were combined to reveal the calcium-binding behaviors of ß-casein phosphopeptides (1-25) (P5) with the best capability in carrying calcium ions. We found that it could carry approximately six calcium ions, and the calcium-binding sites were primarily located at the carbonyl group of Glu-2 and the phosphate group of phosphorylated Ser-15, Ser-18, and Ser-19. An interesting finding was that calcium ions could be bound by three coordinated modes, including unidentate, bidentate and tridentate geometries, resulting in the strong binding abilities. The binding process of calcium ions to P5 was spontaneous with the binding free energies of -5.2 kcal mol-1. Hydrophobic interactions were considered to be the major driving force for the calcium ion binding. The present study provides novel molecular insights into the binding process between Ca2+ and calcium-binding peptides.

Characterization of XtjR8: A novel esterase with phthalate-hydrolyzing activity from a metagenomic library of lotus pond sludge.

A fosmid metagenomic library containing 9.7 × 104 clones was constructed. A novel esterase, XtjR8, was isolated through functional screening. XtjR8 shared the maximum amino acid identity (44%) with acetyl-hydrolase from Streptomyces hygroscopicus, and was classified into family IV esterase. XtjR8 exhibited the highest hydrolytic activity for p-nitrophenyl acetate at 40 °C and pH 8.0, and presented more than 40% activity from 20 °C to 80 °C. More importantly, XtjR8 displayed the ability to hydrolyze both phthalate monoesters and diesters, this feature is extremely rare among previously reported esterases. Site-directed mutagenesis experiments revealed that the catalytic triad residues were Ser152, Glu246, and His276. Among them, Ser152 formed a hydrogen bond with dibutyl phthalate (DBP) by molecular docking, Gly84, Gly85, and Leu248 of conserved motifs formed hydrophobic interactions with DBP, respectively, which were important for the catalytic activity. Considering its wide range of temperature and hydrolytic potential toward phthalate esters, XtjR8 will be served as an interesting candidate for biodegradation and industrial applications.