Identification and Characterization of Three Chitinases with Potential in Direct Conversion of Crystalline Chitin into N,N'-diacetylchitobiose.

Chitooligosaccharides (COSs) have been widely used in agriculture, medicine, cosmetics, and foods, which are commonly prepared from chitin with chitinases. So far, while most COSs are prepared from colloidal chitin, chitinases used in preparing COSs directly from natural crystalline chitin are less reported. Here, we characterize three chitinases, which were identified from the marine bacterium Pseudoalteromonas flavipulchra DSM 14401T, with an ability to degrade crystalline chitin into (GlcNAc)2 (N,N'-diacetylchitobiose). Strain DSM 14401 can degrade the crystalline α-chitin in the medium to provide nutrients for growth. Genome and secretome analyses indicate that this strain secretes six chitinolytic enzymes, among which chitinases Chia4287, Chib0431, and Chib0434 have higher abundance than the others, suggesting their importance in crystalline α-chitin degradation. These three chitinases were heterologously expressed, purified, and characterized. They are all active on crystalline α-chitin, with temperature optima of 45-50 °C and pH optima of 7.0-7.5. They are all stable at 40 °C and in the pH range of 5.0-11.0. Moreover, they all have excellent salt tolerance, retaining more than 92% activity after incubation in 5 M NaCl for 10 h at 4 °C. When acting on crystalline α-chitin, the main products of the three chitinases are all (GlcNAc)2, which suggests that chitinases Chia4287, Chib0431, and Chib0434 likely have potential in direct conversion of crystalline chitin into (GlcNAc)2.

Polyextremophilic Chitinolytic Activity by a Marine Strain (IG119) of Clonostachys rosea.

The investigation for novel unique extremozymes is a valuable business for which the marine environment has been overlooked. The marine fungus Clonostachys rosea IG119 was tested for growth and chitinolytic enzyme production at different combinations of salinity and pH using response surface methodology. RSM modelling predicted best growth in-between pH 3.0 and 9.0 and at salinity of 0-40‱, and maximum enzyme activity (411.137 IU/L) at pH 6.4 and salinity 0‱; however, quite high production (>390 IU/L) was still predicted at pH 4.5-8.5. The highest growth and activity were obtained, respectively, at pH 4.0 and 8.0, in absence of salt. The crude enzyme was tested at different salinities (0-120‱) and pHs (2.0-13.0). The best activity was achieved at pH 4.0, but it was still high (in-between 3.0 and 12.0) at pH 2.0 and 13.0. Salinity did not affect the activity in all tested conditions. Overall, C. rosea IG119 was able to grow and produce chitinolytic enzymes under polyextremophilic conditions, and its crude enzyme solution showed more evident polyextremophilic features. The promising chitinolytic activity of IG119 and the peculiar characteristics of its chitinolytic enzymes could be suitable for several biotechnological applications (i.e., degradation of salty chitin-rich materials and biocontrol of spoiling organisms, possibly solving some relevant environmental issues).

Antifungal potential of Streptomyces rameus GgS 48 against mungbean root rot [Rhizoctonia bataticola (Taub.) Butler].

Mungbean root rot caused by Rhizoctonia bataticola (Taub.) Butler is the most devastating disease inflicting yield loss up to 60%. The use of beneficial antagonist, viz., Streptomyces with diverse antifungal activity and prolific secondary metabolites production, is the ecofriendly and environmentally acceptable alternative to the existing chemical control methods. In this investigation we have identified the promising isolate of Streptomyces sp. which potentially reduced the mungbean root rot. A total of nine mungbean rhizospheric actinobacterial isolates were evaluated for their antagonistic potential against root rot pathogen and growth promoting trait of mungbean. The actinobacterial isolate GgS 48 was shown to be effective in reducing the mycelial growth of R. bataticola by 65.3% in dual culture technique and enhancing the growth of mugbean under in vitro condition. Morphological, biochemical and molecular characterization confirmed the isolate GgS 48 as Streptomyces rameus. The actinobacteria S. rameus GgS 48 exerted antifungal action against R. bataticola by hyphal coiling, which was confirmed under scanning electron microscopy (SEM), and promoted the growth through the production of IAA. It showed positive for the production of siderophore and hydrolytic enzymes, viz., chitinase and protease. The chitinase produced by the GgS 48 was purified and its molecular weight was determined as 40 kDa and it had great potential in reducing the mycelial growth of R. bataticola. The talc-based formulation of S. rameus GgS 48 was found to be promising in suppressing the root rot severity and enhancing the growth and yield attributes of mungbean both under glass house and field conditions.

The discovery and characterization of a novel chitinase with dual catalytic domains from a Qinghai-Tibetan Plateau wetland soil metagenome.

A novel chitinase (P1724) was discovered from a Qinghai-Tibetan plateau microbial metagenome. P1724 contains two GH18 family catalytic domains and is phylogenetically distant from any of the chitinases studied. P1724 and its truncated versions, P1724(∆cGH18) and P1724(∆nGH18), were produced in Escherichia coli and characterized. Using colloidal chitin as substrate, the three recombinant proteins showed maximum hydrolytic activities at 40 °C, pH 5.0-6.0 and 0-0.5 M NaCl, and were cold adaptive, as they remained active at 4 °C; their chitinase activities were decreased with the presence of Cu2+ and EDTA, but increased with Ba2+ and Ca2+; they all showed both chitobiosidase and endochitinase activities. Compared to P1724(∆nGH18), P1724 and P1724(∆cGH18) shared more similarities in temperature and pH stabilities, NaCl tolerance, and substrate affinity, suggesting the N-terminal GH18 domain contributed more than the C-terminal GH18 did in biochemical characteristics of P1724. kcat/Km value of P1724 was significantly higher than the sum values of P1724(∆cGH18) and P1724(∆nGH18), which indicated that two GH18 domains of P1724 worked cooperatively in degrading chitin. This study has not only broadened the understanding of unknown chitinases in nature but also discussed the strategy of adding additional catalytic domains in enzyme engineering.

Biochemical characterization of a GH19 chitinase from Streptomyces alfalfae and its applications in crystalline chitin conversion and biocontrol.

Chitinases play crucial roles in enzymatic conversion of chitin and biocontrol of phytopathogenic fungi. Herein, a chitinase of glycoside hydrolase (GH) family 19, SaChiB, was cloned from Streptomyces alfalfae ACCC 40021 and expressed in Escherichia coli BL21(DE3). The purified SaChiB displayed maximal activities at 45 °C and pH 8.0, and showed good stability up to 55 °C and in the range of pH 4.0-11.0, respectively. It exhibited substrate specificity towards chitin and chitooligosaccharides (degree of polymerization 3-6) with the endo-cleavage manner. In combination with the N-acetyl hexosaminidase SaHEX, it yielded a conversion rate of 95.2% from chitin powder to N-acetyl-D-glucosamine in 8 h and a product purity of >98.5%. Furthermore, the enzyme strongly inhibited the growth of tested pathogenic fungi. These results indicated that SaChiB has the great potential for applications in the conversion of raw chitinous waste in industries as well as the biocontrol of fungal diseases in agriculture.

Insect group II chitinase OfChtII promotes chitin degradation during larva-pupa molting.

The insect group II chitinase (ChtII, also known as Cht10) is a unique chitinase with multiple catalytic and chitin-binding domains. It has been proven genetically to be an essential chitinase for molting. However, ChtII's role in chitin degradation during insect development remains poorly understood. Obtaining this knowledge is the key to fully understanding the chitin degradation system in insects. Here, we investigated the role of OfChtII during the molting of Ostrinia furnacalis, a model lepidopteran pest insect. OfChtII was expressed earlier than OfChtI (OfCht5) and OfChi-h, at both the gene and protein levels during larva-pupa molting as evidenced by quantitative polymerase chain reaction and western blot analyses. A truncated OfChtII, OfChtII-B4C1, was recombinantly expressed in Pichia pastoris cells and purified to homogeneity. The recombinant OfChtII-B4C1 loosened compacted chitin particles and produced holes in the cuticle surface as evidenced by scanning electron microscopy. It synergized with OfChtI and OfChi-h when hydrolyzing insoluble α-chitin. These findings suggested an important role for ChtII during insect molting and also provided a strategy for the coordinated degradation of cuticular chitin during insect molting by ChtII, ChtI and Chi-h.

Purification and characterization of chitinase from Paenibacillus sp. .

The chitinase-producing bacteria Paenibacillus sp. was isolated from soil samples. The chitinase was purified successively by ammonia sulfate fractional precipitation followed by chromatography on DEAE 52-cellulose column and then on Sephadex G-75 column. The chitinase has a molecular weight of ca. 30 kDa as measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) electrophoresis. Its optimum pH is 4.5, and its optimum temperature is 50 °C with colloidal chitin as a substrate. The enzyme is stable below 45 °C and in pH ranges between 4.5 and 5.5. It is activated by glucosamine, glucose, N-acetylglucosamine, and metal ions including Ca2+ , Fe2+ , Fe3+ , and Ni2+ . It is inhibited by SDS, H2 O2 , ascorbic acid, Cu2+ , Mg2+ , Ba2+ , Sn2+ , Cr3+ , and K+ . With colloidal chitin as substrate, the Km and the Vmax of the chitinase are 4.28 mg/mL and 14.29 µg/(Min·mL), respectively, whereas the end products of the enzymatic hydrolysis are 14.33% monomer and 85.67% dimer of N-acetylglucosamine. The viscosity of carboxymethyl chitin decreased rapidly at the initial stages when subjected to chitinase hydrolysis, which indicates that the chitinase acts in an endosplitting pattern.

Biochemical and molecular characterization of an acido-thermostable endo-chitinase from Bacillus altitudinis KA15 for industrial degradation of chitinous waste.

This paper reports the isolation and identification of an acido-thermostable chitinase (ChiA-Ba43) which was purified, from the culture liquid of Bacillus altitudinis strain KA15, and characterized. Purification of ChiA-Ba43 produced a 69.6-fold increase in the specific activity (120,000 U/mg) of the chitinase, with a yield of 51% using colloidal chitin as substrate. ChiA-Ba43 was found to be a monomeric protein with a molecular mass of 43,190.05 Da as determined by MALDI-TOF/MS. N-terminal sequence of the first 27 amino-acids (aa) of ChiA-Ba43 displayed homology to chitinases from other Bacillus species. Interestingly, ChiA-Ba43 exhibited optimum pH and temperature of 4-5.5 and 85 °C, respectively. Thin-layer chromatography (TLC) showed that the final hydrolyzed products of the enzyme from chitin-oligosaccharides and colloidal chitin are a mixture of (GlcNAc)2, (GlcNAc)3, (GlcNAc)4, and (GlcNAc)5, which indicates that ChiA-Ba43 possesses an endo-acting function. More interestingly, compared to ChiA-Mt45, ChiA-Hh59, Chitodextrinase®, N-acetyl-ß-glucosaminidase®, and ChiA-65, ChiA-Ba43 demonstrated a high level of catalytic efficiency and outstanding tolerance towards various organic solvents. The chiA-Ba43 gene (1332 bp) encoding ChiA-Ba43 (409 aa) was cloned, sequenced, and expressed in Escherichia coli strain HB101. The biochemical properties of the recombinant chitinase (rChiA-Ba43) were equivalent to those of the natively expressed enzyme. These properties make ChiA-Ba43 an ideal candidate for industrial bioconversion of chitinous waste.

Structure of intact chitinase with hevein domain from the plant Simarouba glauca, known for its traditional anti-inflammatory efficacy.

Chitinase from the leaves of Simarouba glauca, a plant used in traditional anti-inflammatory therapy is purified and characterized. Peptide mass finger print analysis revealed the protein as an endo-chitinase which was further confirmed using chitin-agar assay. The enzyme exhibited significant anti-fungal efficacy against phyto-pathogens such as Macrophomina phaseolina, Fusarium oxysporum and Sclerotium rolfsii. Chitinolysis was also examined against insoluble chitin using SEM. Using X-ray diffraction data up to 1.66 Å, the structure was determined by Molecular Replacement using crystal structure of GH19 Chitinase-like protein from Hevea brasiliensis. During structure refinement, an extra domain could be traced and identified as hevein domain. To our knowledge, this is the first report of any chitinase with intact hevein domain. The GH19 chitinase and hevein domains though connected by a lengthy loop, are restricted to be close by disulfide bridges. These bridges connecting each domain with the loop may be important for proper chitin feeding into the active site. By considering reports on hevein and chitinase domains as well as the traditional use of the plant, this report of an intact hevein-chitinase protein and their relative orientation may add further insights for the usefulness of this protein.

Bioconversion of chitin and concomitant production of chitinase and N-acetylglucosamine by novel Achromobacter xylosoxidans isolated from shrimp waste disposal area.

Marine pollution is a significant issue in recent decades, with the increase in industries and their waste harming the environment and ecosystems. Notably, the rise in shellfish industries contributes to tons of shellfish waste composed of up to 58% chitin. Chitin, the second most ample polymer next to cellulose, is insoluble and resistant to degradation. It requires chemical-based treatment or enzymatic hydrolysis to cleave the chitin polymers. The chemical-based treatment can lead to environmental pollution, so to solve this problem, enzymatic hydrolysis is the best option. Moreover, the resulting biopolymer by-products can be used to boost the fish immune system and also as drug delivery agents. Many marine microbial strains have chitinase producing ability. Nevertheless, we still lack an economical and highly stable chitinase enzyme for use in the industrial sector. So we isolate a novel marine bacterial strain Achromobacter xylosoxidans from the shrimp waste disposal site using chitin minimal medium. Placket-Burman and central composite design statistical models for culture condition optimisation predicted a 464.2 U/ml of chitinase production. The culture conditions were optimised for maximum chitinase production recording up to 467 U/ml. This chitinase from the A. xylosoxidans was 100% active at an optimum temperature of 45 °C (withstand up to 55 °C) and pH 8 with 80% stability. The HPLC analysis of chitinase degraded shellfish waste reveals a major amino acid profile composition-arginine, lysine, aspartic acid, alanine, threonine and low levels of isoleucine and methionine. These chitinase degraded products and by-products can be used as supplements in the aquaculture industry.

Cloning, characterization, and functional analysis of chitinase-like protein 1 in the shell of Pinctada fucata.

Biomineralization, especially shell formation, is a sophisticated process regulated by various matrix proteins. Pinctada fucata chitinase-like protein 1 (Pf-Clp1), which belongs to the GH18 family, was discovered by our group using in-depth proteomic analysis. However, its function is still unclear. In this study, we first obtained the full-length cDNA sequence of Pf-Clp1 by RACE. Real-time polymerase chain reaction results revealed that Pf-Clp1 was highly expressed in the important biomineralization tissues, the mantle edge and the mantle pallial. We expressed and purified recombinant protein rPf-Clp1 in vitro to investigate the function of Pf-Clp1 on CaCO3 crystallization. Scanning electron microscopy imaging and Raman spectroscopy revealed that rPf-Clp1 was able to affect the morphologies of calcite crystal in vitro. Shell notching experiments suggested that Pf-Clp1 might function as a negative regulator during shell formation in vivo. Knockdown of Pf-Clp1 by RNAi led to the overgrowth of aragonite tablets, further confirming its potential negative regulation on biomineralization, especially in the nacreous layer. Our work revealed the potential function of molluscan Clp in shell biomineralization for the first time and unveiled some new understandings toward the molecular mechanism of shell formation.

Creation of Chitinase Producer and Disruption of Micromycete Cell Wall with the Obtained Enzyme Preparation.

A recombinant strain producing a complex of extracellular enzymes including chitinase from Myceliophtora thermophila was created based on the fungus Penicillium verruculosum. The activity of the enzyme preparations obtained from the cultural fluid of the producer strain was 0.55, 0.53, and 0.66 U/mg protein with chitin and chitosans with the molecular weight of 200 and 1000 kDa, respectively. The temperature optimum for the recombinant chitinase was 52-65°C; the pH optimum was 4.5-6.2, which corresponded to the published data for this class of the enzymes. The content of heterologous chitinase in the obtained enzyme preparations was 47% of total protein content in the cultural fluid. Enzyme preparations produced by the recombinant P. verruculosum XT403 strain and containing heterologous chitinase were able to degrade the mycelium of micromycetes, including phytopathogenic ones, and were very efficient in the bioconversion of microbiological industry waste.

Kilbournase, a protease-associated domain subtilase secreted by the fungal corn pathogen Stenocarpella maydis.

Subtilases are a large family of serine proteases that occur throughout biology. A small subset contain protease-associated (PA) domains that are structurally separate from but encoded within the active site. In bacteria, subtilase PA domains function to recruit specific protein substrates. Here we demonstrate that a protease secreted by the fungal corn pathogen Stenocarpella maydis, which truncates corn ChitA chitinase, is a PA domain subtilase. Protease was purified from S. maydis cultures and tryptic peptides were analyzed by LC-MS/MS. Ions were mapped to two predicted PA domain subtilases. Yeast strains were engineered to express each protease. One failed to produce recombinant protein while the other secreted protease that truncated ChitA. This protease, that we named kilbournase, was purified and characterized. It cleaved multiple peptide bonds in the amino-terminal chitin binding domain of ChitA while leaving the catalytic domain intact. Kilbournase was more active on the ChitA-B73 alloform compared to ChitA-LH82 and did not cleave AtChitIV3, a homolog from Arabidopsis thaliana, indicating a high level of specificity. Truncation of corn ChitA by kilbournase resembles truncation of human C5a by Streptococcus pyogenes ScpA, arguing that PA domain proteases in bacteria and fungi may commonly target specific host proteins.

Novel insecticidal chitinase from the insect pathogen Xenorhabdus nematophila.

Xenorhabdus nematophila strain ATCC 19061 is an insect pathogen that produces various protein toxins which intoxicate and kill its larval host. In the present study, we have described the cloning, expression and characterization of a 76-kDa chitinase protein of X. nematophila. A 1.9 kb DNA sequence encoding the chitinase gene was PCR amplified and cloned. Further, the chitinase protein was expressed in Escherichia coli and purified by using affinity chromatography. Two highly conserved domains were identified GH18 and ChiA. The purified chitinase protein showed chitobiosidase activity, ß-N-acetylglucosaminidase and endochitinase activity, when enzyme activity was measured using respective substrates. The purified chitinase protein was found to be orally toxic to the larvae of a major crop pest, Helicoverpa armigera when fed to the larvae mixed with artificial diet. It also had adverse effect on the growth and development of the surviving larvae. Surviving larvae showed 9-fold reduction in weight, as a result the transformation of larvae into pupae was adversely affected. Our results demonstrated that the chitinase protein of X. nematophila has insecticidal property and can prove to be a potent candidate for pest control in plants.

Performance of antifreeze protein HrCHI4 from Hippophae rhamnoides in improving the structure and freshness of green beans upon cryopreservation.

Antifreeze proteins restrict the growth of ice crystals during recrystallization and therefore find application in the protection of food products from damage upon freezing. Hippophae rhamnoides (seabuckthorn) is a freeze tolerant Himalayan shrub exhibiting antifreeze properties. Here, ~39 kDa class IV chitinase (HrCHI4) was purified from seabuckthorn seeds using chitin-affinity chromatography that showed antifreeze property by ice recrystallization inhibition. The application of HrCHI4 in cryopreservation of green beans was analyzed to verify its antifreeze potential. HrCHI4 pretreatment reduced the drip loss and electrolytic leakage in frozen beans, revealing that it preserved the membrane integrity upon cryopreservation. The texture analysis and SEM further validated structural maintenance. The volatile component analysis using GC-MS was performed to evaluate the quality of frozen beans. HrCHI4 contributed positively towards the retention of volatile components after freeze-thaw. In conclusion, a class IV chitinase HrCHI4 was purified from seabuckthorn seeds and its cryoprotective function was reported.

Expression and characterization of a chitinase from Serratia marcescens.

A chitinase gene from Serratia marcescens was cloned and expressed in Escherichia coli BL21(DE3) and the properties of recombinant chitinase rCHI-2 were characterized. The optimum catalytic pH of rCHI-2 was 6.0. It was stable in the pH range of 6.0-9.0 and could maintain more than 90% of its relative enzyme activity after incubation at 37 °C for 1 h. The optimum catalytic temperature of the enzyme was 55 °C and 85% of enzyme activity was remained after incubation at 45 °C for 1 h. The activation energy of the thermal inactivation of the enzyme was 10.9 kJ/mol and the Michaelis-Menten constant was 3.2 g/L. The purified rCHI-2 was found to be highly stable at 45 °C with half-life (t1/2) of 289 min and thermodynamic parameters ΔH*, ΔG* and ΔS* revealed high affinity of rCHI-2 for chitin. Hg2+ was found to be able to inhibit the enzyme activity reversibly, while IC50 and inhibition constant of Hg2+ on the enzyme were 34.8 µmol/L and 44.6 µmol/L, respectively. Moreover, rCHI-2 could specifically hydrolyze colloidal chitin into GlcNAc2 as the major product.

Statistical Optimization for Coproduction of Chitinase and Beta 1, 4-Endoglucanase by Chitinolytic Paenibacillus elgii PB1 Having Antifungal Activity.

A bacterial strain PB1 with antagonistic activity against pathogenic fungi was isolated from marine soil and was identified as Paenibacillus elgii based on phenotypic and genotypic characterization. The isolate showed good antifungal activity against "Aspergillus niger (MTCC 282), Trichophyton rubrum (MTCC 791), Microsporum gypseum (MTCC 2819), Candida albicans (MTCC 227), and Saccharomyces cerevisiae (MTCC 170)". Chitinase and beta 1, 4-endoglucanase are known for their capability to degrade fungal cell wall, thus we analyzed its productivity in PB1 strain using Plackett-Burman and Central Composite Design. The factors that affect the productivity of chitinase and beta 1, 4-endoglucanase were identified and optimized. A 7.77-fold increase (3.157 to 24.53 ± 1.33 U/mL) in chitinase and 7.422-fold increase (6.476 to 48.066 ± 0.676 U/mL) in beta 1, 4-endoglucanase versus basal medium was achieved. Chitinase and beta 1, 4-endoglucanase produced by Paenibacillus elgii strain PB1 represents the new source for biotechnological, medical, and agricultural applications.

Antifungal Proteins from Plant Latex.

Latex, a milky fluid found in several plants, is widely used for many purposes, and its proteins have been investigated by researchers. Many studies have shown that latex produced by some plant species is a natural source of biologically active compounds, and many of the hydrolytic enzymes are related to health benefits. Research on the characterization and industrial and pharmaceutical utility of latex has progressed in recent years. Latex proteins are associated with plants' defense mechanisms, against attacks by fungi. In this respect, there are several biotechnological applications of antifungal proteins. Some findings reveal that antifungal proteins inhibit fungi by interrupting the synthesis of fungal cell walls or rupturing the membrane. Moreover, both phytopathogenic and clinical fungal strains are susceptible to latex proteins. The present review describes some important features of proteins isolated from plant latex which presented in vitro antifungal activities: protein classification, function, molecular weight, isoelectric point, as well as the fungal species that are inhibited by them. We also discuss their mechanisms of action.

A Cold-Adapted Chitinase-Producing Bacterium from Antarctica and Its Potential in Biocontrol of Plant Pathogenic Fungi.

To obtain chitinase-producing microorganisms with high chitinolytic activity at low temperature, samples collected from Fildes Peninsula in Antarctica were used as sources for bioprospecting of chitinolytic microorganisms. A cold-adapted strain, designated as GWSMS-1, was isolated from marine sediment and further characterized as Pseudomonas. To improve the chitinase production, one-factor-at-a-time and orthogonal test approaches were adopted to optimize the medium components and culture conditions. The results showed that the highest chitinolytic activity (6.36 times higher than that before optimization) was obtained with 95.41 U L-1 with 15 g L-1 of glucose, 1 g L-1 of peptone, 15 g L-1 of colloid chitin and 0.25 g L-1 of magnesium ions contained in the medium, cultivated under pH 7.0 and a temperature of 20 °C. To better understand the application potential of this strain, the enzymatic properties and the antifungal activity of the crude chitinase secreted by the strain were further investigated. The crude enzyme showed the maximum catalytic activity at 35 °C and pH 4.5, and it also exhibited excellent low-temperature activity, which still displayed more than 50% of its maximal activity at 0 °C. Furthermore, the crude chitinase showed significant inhibition of fungi Verticillium dahlia CICC 2534 and Fusarium oxysporum f. sp. cucumerinum CICC 2532, which can cause cotton wilt and cucumber blight, respectively, suggesting that strain GWSMS-1 could be a competitive candidate for biological control in agriculture, especially at low temperature.

The potential of plant and fungal proteins in the control of gastrointestinal nematodes from animals.

Gastrointestinal nematode infection is an important cause of high economic losses in livestock production. Nematode control based on a synthetic chemical approach is considered unsustainable due to the increasing incidence of anthelmintic resistance. Control alternatives such as the use of natural products are therefore becoming relevant from an environmental and economic point of view. Proteins are macromolecules with various properties that can be obtained from a wide range of organisms, including plants and fungi. Proteins belonging to different classes have shown great potential for the control of nematodes. The action of proteins can occur at specific stages of the nematode life cycle, depending on the composition of the external layers of the nematode body and the active site of the protein. Advances in biotechnology have resulted in the emergence of numerous protein and peptide therapeutics; however, few have been discussed with a focus on the control of animal nematodes. Here, we discuss the use of exogenous proteins and peptides in the control of gastrointestinal.