Microbial-derived salt-tolerant proteases and their applications in high-salt traditional soybean fermented foods: a review

Abstract

Different microorganisms can produce different proteases, which can adapt to different industrial requirements such as pH, temperature, and pressure. Salt-tolerant proteases (STPs) from microorganisms exhibit higher salt tolerance, wider adaptability, and more efficient catalytic ability under extreme conditions compared to conventional proteases. These unique enzymes hold great promise for applications in various industries including food, medicine, environmental protection, agriculture, detergents, dyes, and others. Scientific studies on microbial-derived STPs have been widely reported, but there has been little systematic review of microbial-derived STPs and their application in high-salt conventional soybean fermentable foods. This review presents the STP-producing microbial species and their selection methods, and summarizes and analyzes the salt tolerance mechanisms of the microorganisms. It also outlines various techniques for the isolation and purification of STPs from microorganisms and discusses the salt tolerance mechanisms of STPs. Furthermore, this review demonstrates the contribution of modern biotechnology in the screening of novel microbial-derived STPs and their improvement in salt tolerance. It highlights the potential applications and commercial value of salt-tolerant microorganisms and STPs in high-salt traditional soy fermented foods. The review ends with concluding remarks on the challenges and future directions for microbial-derived STPs. This review provides valuable insights into the separation, purification, performance enhancement, and application of microbial-derived STPs in traditional fermented foods.

Keywords

Application / Mechanism / Microorganism / Modern biotechnology / Salt tolerance / Salt-tolerant protease / Soy fermentable foods

References

Abanoz B, Okay S, Kurt-Kizildogan A, . Highly active and stable protease production by an extreme halophilic archaeon Haloarcula sp. TG1 isolated from Lake Tuz. Turkey. Turkish J Biochem, 2017, 42(3): 307-315.

Abdel-Hamed AR, Abo-Elmatty DM, Wiegel J, . Biochemical characterization of a halophilic, alkalithermophilic protease from Alkalibacillus sp. NM-Da2. Extremophiles, 2016, 20(6): 885-894.

Aguiar-Pulido V, Huang WR, Suarez-Ulloa V, . Metagenomics, metatranscriptomics, and metabolomics approaches for microbiome analysis. Evol Bioinform, 2016, 12: 5-16.

Aguilar JGD, Sato HH. Microbial proteases: Production and application in obtaining protein hydrolysates. Food Res Int, 2018, 103: 253-262.

Ahmad S, Kumar V, Ramanand KB, . Probing protein stability and proteolytic resistance by loop scanning: a comprehensive mutational analysis. Protein Sci, 2012, 21(3): 433-446.

Altinkaynak C, Tavlasoglu S, Ozdemir N, . A new generation approach in enzyme immobilization: Organic-inorganic hybrid nanoflowers with enhanced catalytic activity and stability. Enzyme Microb Technol, 2016, 93–94: 105-112.

An FY, Wu JR, Feng YZ, . A systematic review on the flavor of soy-based fermented foods: Core fermentation microbiome, multisensory flavor substances, key enzymes, and metabolic pathways. Compr Rev Food Sci F, 2023, 22(4): 2773-2801.

Anh HTH, Shahsavari E, Bott NJ, . Options for improved treatment of saline wastewater from fish and shellfish processing. Front Env Sci-Switz, 2021, 9.

Ao XL, Yu X, Wu DT, . Purification and characterization of neutral protease from Aspergillus oryzae Y1 isolated from naturally fermented broad beans. AMB Express, 2018, 8: 96.

Ashraf NM, Krishnagopal A, Hussain A, . Engineering of serine protease for improved thermostability and catalytic activity using rational design. Int J Biol Macromol, 2019, 126: 229-237.

Banerjee G, Ray AK. Impact of microbial proteases on biotechnological industries. Biotechnol Genet Eng, 2017, 33(2): 119-143.

Boon L, Ugarte-Berzal E, Vandooren J, . Protease propeptide structures, mechanisms of activation, and functions. Crit Rev Biochem Mol Biol, 2020, 55(2): 111-165.

Britton KL, Stillman TJ, Yip KSP, . Insights into the molecular basis of salt tolerance from the study of glutamate dehydrogenase from Halobacterium salinarum. J Biol Chem, 1998, 273(15): 9023-9030.

Britton KL, Baker PJ, Fisher M, . Analysis of protein solvent interactions in glucose dehydrogenase from the extreme halophile Haloferax mediterranei. Proc Natl Acad Sci U S A, 2006, 103(13): 4846-4851.

Busche T, Tsolis KC, Koepff J, . Multi-omics and targeted approaches to determine the role of cellular proteases in streptomyces protein secretion. Front Microbiol, 2018, 9: 1174.

Cai LN, Xu SN, Lu T, . Salt-tolerant and thermostable mechanisms of an endoglucanase from marine Aspergillus niger. Bioresour Bioprocess, 2022, 9(1): 44.

Chanalia P, Gandhi D, Jodha D, . Applications of microbial proteases in pharmaceutical industry: an overview. Rev Med Microbiol, 2011, 22(4): 96-101.

Chauhan JV, Mathukiya RP, Singh SP, . Two steps purification, biochemical characterization, thermodynamics and structure elucidation of thermostable alkaline serine protease from Nocardiopsis alba strain OM-5. Int J Biol Macromol, 2021, 169: 39-50.

Chen X, Wang WW, Hu HY, . Insights from comparative proteomic analysis into degradation of phenanthrene and salt tolerance by the halophilic Martelella strain AD-3. Ecotoxicology, 2021, 30(7): 1499-1510.

Chen CF, Hou S, Wu CZ, . Improving protein utilization and fermentation quality of soy sauce by adding protease. J Food Compost Anal, 2023, 121.

Cheng YQ, Hu Q, Li LT, . Production of Sufu, a traditional Chinese fermented soybean food, by fermentation with Mucor flavus at low temperature. Food Sci Technol Res, 2009, 15(4): 347-352.

Chou CC, Hwan CH. Effect of ethanol on the hydrolysis of protein and lipid during the aging of a chinese fermented soya bean curd—Sufu. J Sci Food Agric, 1994, 66(3): 393-398.

Chun BH, Kim KH, Jeong SE, . The effect of salt concentrations on the fermentation of doenjang, a traditional Korean fermented soybean paste. Food Microbiol, 2020, 86.

Chung D, Yu WJ, Lim JY, . Characterization of the proteolytic Activity of a Halophilic Aspergillus reticulatus Strain SK1-1 Isolated from a solar saltern. Microorganisms, 2022, 10(1): 29.

Daoud L, Hmani H, Ben Ali M, . An original halo-alkaline protease from Bacillus halodurans Strain US₁₉₃: biochemical characterization and potential use as bio-additive in detergents. J Polym Environ, 2018, 26(1): 23-32.

Dong L, Qi SJ, Jia JW, . Enantioselective resolution of (+/-)-1-phenylethyl acetate using the immobilized extracellular proteases from deep-sea Bacillus sp. DL-1. Biocatal Biotransform, 2022, 40(4): 258-274.

Dym O, Mevarech M, Sussman JL, . Structural features that stabilize halophilic malate-dehydrogenase from an archaebacterium. Science, 1995, 267(5202): 1344-1346.

Ebel C, Faou P, Kernel B, . Relative role of anions and cations in the stabilization of halophilic malate dehydrogenase. Biochemistry, 1999, 38(28): 9039-9047.

Edbeib MF, Wahab RA, Huyop F, . Halophiles: biology, adaptation, and their role in decontamination of hypersaline environments. World J Microbiol Biotechnol, 2016, 32(8): 135.

Enache M, Kamekura M. Hydrolytic enzymes of halophilic microorganisms and their economic values. Rom J Biochem, 2010, 47(1): 47-59.

Essghaier B, Bejji M, Jijakli H, . High salt-tolerant protease from a potential biocontrol agent Bacillus pumilus M3–16. Ann Microbiol, 2009, 59(3): 553-558.

Falkenberg F, Rahba J, Fischer D, . Biochemical characterization of a novel oxidatively stable, halotolerant, and high-alkaline subtilisin from Alkalihalobacillus okhensis Kh10-101^T. FEBS Open Bio, 2022, 12(10): 1729-1746.

Feng Z, Chen H, Lv XT, . Accelerated ripening of Kedong sufu with autochthonous starter cultures Kocuria rosea KDF3 and its protease KP3 as adjuncts. J Appl Microbiol, 2014, 116(4): 877-889.

Feng HJ, Chen L, Ding YC, . Mechanism on the microbial salt tolerance enhancement by electrical stimulation. Bioelectrochemistry, 2022, 147.

Flores-Santos JC, Zavaleta AI, Flores-Fernandez CN, . Production and characterization of extremophilic proteinases from a new enzyme source, Barrientosiimonas sp. V9. Appl Biochem Biotechnol, 2020, 190(3): 1060-1073.

Foophow T, Sittipol D, Rukying N, . Purification and characterization of a novel extracellular haloprotease Vpr from Bacillus licheniformis strain KB111. Food Technol Biotechnol, 2022, 60(2): 225-236.

Fu XT, You SG, Kim SM, . Characterization of a salt-tolerant acid protease produced by Bacillus megaterium KLP-98 and its potential as a fermentation starter for the manufacture of fish sauce. J Food Biochem, 2008, 32(3): 279-298.

Fujisawa M, Kusumoto A, Wada Y, . NhaK, a novel monovalent cation/H⁺ antiporter of Bacillus subtilis. Arch Microbiol, 2005, 183(6): 411-420.

Fukuchi S, Yoshimune K, Wakayama M, . Unique amino acid composition of proteins in halophilic bacteria. J Mol Biol, 2003, 327(2): 347-357.

Funaki J, Yano M, Misaka T, . Purification and characterization of a neutral protease that contributes to the unique flavor and texture of Tofu-misozuke. J Food Biochem, 1997, 21(3): 191-202.

Gao XL, Zhao HF, Feng YZ, . A comparative study on physicochemical properties of Chinese-type soy sauces prepared using pure koji and mixed kojis. Afr J Biotechnol, 2010, 9(40): 6740-6747.

Gao RC, Shi T, Liu XD, . Purification and characterisation of a salt-stable protease from the halophilic archaeon Halogranum rubrum. J Sci Food Agric, 2017, 97(5): 1412-1419.

Gao XL, Yin YY, Zhou CS, . Purification, characterisation and salt-tolerance molecular mechanisms of aspartyl aminopeptidase from Aspergillus oryzae 3.042. Food Chem, 2018, 240: 377-385.

Gao XL, Yin YY, Yan JK, . Separation, biochemical characterization and salt-tolerant mechanisms of alkaline protease from Aspergillus oryzae. J Sci Food Agric, 2019, 99(7): 3359-3366.

Gao XL, Liu EM, Yin YY, . Enhancing activities of salt-tolerant proteases secreted by Aspergillus oryzae using atmospheric and room-temperature plasma mutagenesis. J Agric Food Chem, 2020, 68(9): 2757-2764.

Gaonkar SK, Furtado IJ. Characterization of extracellular protease from the Haloarcheon Halococcus sp. strain GUGFAWS-3 (MF425611). Curr Microbiol, 2020, 77(6): 1024-1034.

Garcia-Moyano A, Diaz Y, Navarro J, . Two-step functional screen on multiple proteinaceous substrates reveals temperature-robust proteases with a broad-substrate range. Appl Microbiol Biotechnol, 2021, 105(8): 3195-3209.

Ge CX, Wang YG, Lu SP, . Multi-omics analyses reveal the regulatory network and the function of ZmUGTs in maize defense response. Front Plant Sci, 2021, 12.

Ghafoori H, Askari M, Sarikhan S, . Purification and characterization of an extracellular haloalkaline serine protease from the moderately halophilic bacterium, Bacillus iranensis (X5B). Extremophiles, 2016, 20(2): 115-123.

Gomari MM, Saraygord-Afshari N, Farsimadan M, . Opportunities and challenges of the tag-assisted protein purification techniques: applications in the pharmaceutical industry. Biotechnol Adv, 2020, 45.

González-Hernández J, Peña A. Adaptation strategies of halophilic microorganisms and Debaryomyces hansenii (halophilic yeast). Rev Latinoam Microbiol, 2002, 44: 137-156.

Gromiha MM, Oobatake M, Kono H, . Role of structural and sequence information in the prediction of protein stability changes: comparison between buried and partially buried mutations. Protein Eng, 1999, 12(7): 549-555.

Gu Y, Tian JJ, Zhang Y, . Dissecting signal molecule AI-2 mediated biofilm formation and environmental tolerance in Lactobacillus plantarum. J Biosci Bioeng, 2021, 131(2): 153-160.

Han BZ, Rombouts FM, Nout MJR, . A Chinese fermented soybean food. Int J Food Microbiol, 2001, 65(1–2): 1-10.

Han BZ, Wang JH, Rombouts FM, . Effect of NaCl on textural changes and protein and lipid degradation during the ripening stage of sufu, a Chinese fermented soybean food. J Sci Food Agric, 2003, 83(9): 899-904.

Han BZ, Rombouts FM, Nout MJR, . Amino acid profiles of sufu, a Chinese fermented soybean food. J Food Compost Anal, 2004, 17(6): 689-698.

Hanefeld U, Cao LQ, Magner E, . Enzyme immobilisation: fundamentals and application. Chem Soc Rev, 2013, 42(15): 6211-6212.

Hao JY, Zhang ZC, Yang M, . Micronization using combined alkaline protease hydrolysis and high-speed shearing homogenization for improving the functional properties of soy protein isolates. Bioresour Bioprocess, 2022, 9(1): 77.

He WM, Chung HY. Exploring core functional microbiota related with flavor compounds involved in the fermentation of a natural fermented plain sufu (Chinese fermented soybean curd). Food Microbiol, 2020, 90.

He WM, Chen ZX, Chun HY, . Dynamic correlations between major enzymatic activities, physicochemical properties and targeted volatile compounds in naturally fermented plain sufu during production. Food Chem, 2022, 378.

Heng XY, Chen HY, Lu CX, . Study on synergistic fermentation of bean dregs and soybean meal by multiple strains and proteases. LWT-Food Sci Technol, 2022, 154.

Hou Y, Lu F, Tian J, . Cloning, heterologous expression and characterization of an intracellular serine protease from Bacillus sp. LCB10. Appl Biochem Microbiol, 2019, 55(5): 482-488.

Hou J, Han D, Zhou Y, . Identification and characterization of the gene encoding an extracellular protease from haloarchaeon Halococcus salifodinae. Microbiol Res, 2020, 236.

Hou J, Yin XM, Li Y, . Biochemical characterization of a low salt-adapted extracellular protease from the extremely halophilic archaeon Halococcus salifodinae. Int J Biol Macromol, 2021, 176: 253-259.

Hu X, Li DH, Qiao Y, . Salt tolerance mechanism of a hydrocarbon-degrading strain: salt tolerance mediated by accumulated betaine in cells. J Hazard Mater, 2020, 392.

Hu Y, Li T, Tu Z, . Engineering a recombination neutral protease I from Aspergillus oryzae to improve enzyme activity at acidic pH. RSC Adv, 2020, 10(51): 30692-30699.

Hu XL, Zhao X, Wang MX, . Rationally tailoring the halophilicity of an amylolytic enzyme for application in dehydrating conditions. Biochem Eng J, 2022, 189.

Ibrahim ASS, Al-Salamah AA, El-Badawi YB, . Detergent-, solvent- and salt-compatible thermoactive alkaline serine protease from halotolerant alkaliphilic Bacillus sp. NPST-AK15: purification and characterization. Extremophiles, 2015, 19(5): 961-971.

Ibrahim ASS, Al-Salamah AA, Elbadawi YB, . Production of extracellular alkaline protease by new halotolerant alkaliphilic Bacillus sp. NPST-AK15 isolated from hyper saline soda lakes. Electron J Biotechnol, 2015, 18(3): 236-243.

Ibrahim ASS, Al-Salamah AA, Elbadawi YB, . Alkaline protease from a new halotolerant alkaliphilic Bacillus agaradhaerens strain AK-R isolated from Egyptian soda lakes. Biosci J, 2016, 32(6): 1604-1618.

Ibrahim ASS, Elbadawi YB, El-Tayeb MA, . Alkaline serine protease from the new halotolerant alkaliphilic Salipaludibacillus agaradhaerens strain AK-R: purification and properties. 3 Biotech, 2019, 9(11): 391.

Ibrahim ASS, Elbadawi YB, El-Toni AM, . Stabilization and improved properties of Salipaludibacillus agaradhaerens alkaline protease by immobilization onto double mesoporous core-shell nanospheres. Int J Biol Macromol, 2021, 166: 557-566.

Johnson J, Yang YH, Lee DG, . Expression, purification and characterization of halophilic protease Pph_Prol cloned from Pseudoalteromonas phenolica. Protein Expression Purif, 2018, 152: 46-55.

Jothi Basu M, Indra V, Hemapriya J, . Bioprocess optimization of halophilic protease production by a halophilic bacterial strain JS4. Int J Curr Res Aca Rev, 2015, 3(4): 309-315.

Kalwasinska A, Jankiewicz U, Felfoldi T, . Alkaline and halophilic protease production by Bacillus luteus H11 and its potential industrial applications. Food Technol Biotechnol, 2018, 56(4): 553-561.

Karan R, Capes MD, Dassarma S, . Function and biotechnology of extremophilic enzymes in low water activity. Aquat Biosyst, 2012, 8(1): 4.

Kilcawley KN, Nongonierma AB, Hannon JA, . Evaluation of commercial enzyme systems to accelerate Cheddar cheese ripening. Int Dairy J, 2012, 26(1): 50-57.

Kurt-Kizildogan A, Abanoz B, Okay S, . Global transcriptome analysis of Halolamina sp. to decipher the salt tolerance in extremely halophilic archaea. Gene, 2017, 601: 56-64.

Lam MQ, Mut NNN, Thevarajoo S, . Characterization of detergent compatible protease from halophilic Virgibacillus sp CD6. 3 Biotech, 2018, 8: 104.

Lario LD, Chaud L, Almeida MD, . Production, purification, and characterization of an extracellular acid protease from the marine Antarctic yeast Rhodotorula mucilaginosa L7. Fungal Biol, 2015, 119(11): 1129-1136.

Lee SK, Hwang JY, Choi SH, . Purification and characterization of Aspergillus oryzae LK-101 salt-tolerant acid protease isolated from soybean paste. Food Sci Biotechnol, 2010, 19(2): 327-334.

Lefebvre O, Moletta R. Treatment of organic pollution in industrial saline wastewater: a literature review. Water Res, 2006, 40(20): 3671-3682.

Lei FF, Zhao QZ, Sun-Waterhouse DX, . Characterization of a salt-tolerant aminopeptidase from marine Bacillus licheniformis SWJS33 that improves hydrolysis and debittering efficiency for soy protein isolate. Food Chem, 2017, 214: 347-353.

Leng XW, Xu Y. Improvement of acid protease production by a mixed culture of Aspergillus niger and Aspergillus oryzae using solid-state fermentation technique. Afr J Biotechnol, 2011, 10(35): 6824-6829.

Li YY, Yu RC, Chou CC, . Some biochemical and physical changes during the preparation of the enzyme-ripening sufu, a fermented product of soybean curd. J Agric Food Chem, 2010, 58(8): 4888-4893.

Li YC, Ku S, Park MS, . Acceleration of aglycone isoflavone and gamma-aminobutyric acid production from Doenjang using whole-cell biocatalysis accompanied by protease treatment. J Microbiol Biotechnol, 2017, 27(11): 1952-1960.

Li C, Li W, Li H, . The effect of quorum sensing on performance of salt-tolerance aerobic granular sludge: linking extracellular polymeric substances and microbial community. Biodegradation, 2019, 30(5–6): 447-456.

Li PS, Kong WL, Wu XQ, . Salt tolerance mechanism of the rhizosphere bacterium JZ-GX1 and its effects on tomato seed germination and seedling growth. Front Microbiol, 2021, 12.

Li XJ, He Y, Yang W, . Comparative analysis of the microbial community and nutritional quality of sufu. Food Sci Nutr, 2021, 9(8): 4117-4126.

Liang YC, Pan L, Lin Y, . Analysis of extracellular proteins of Aspergillus oryzae grown on Soy Sauce Koji. Biosci Biotechnol Biochem, 2009, 73(1): 192-195.

Liang LW, Fei X, Li Y, . Hierarchical assembly of enzyme-inorganic composite materials with extremely high enzyme activity. RSC Adv, 2015, 5(117): 96997-97002.

Lim J, Choi YH, Hurh BS, . Strain improvement of Aspergillus sojae for increased l-leucine aminopeptidase and protease production. Food Sci Biotechnol, 2019, 28(1): 121-128.

Lin Z, Xiao Y, Wang L, . Facile synthesis of enzyme-inorganic hybrid nanoflowers and their application as an immobilized trypsin reactor for highly efficient protein digestion. RSC Adv, 2014, 4(27): 13888-13891.

Lin HB, Zhou BB, Zhao JH, . Insight into the protein degradation during the broad bean fermentation process. Food Sci Nutr, 2022, 10(8): 2760-2772.

Liu JJ, Li DS, Hu Y, . Effect of a halophilic aromatic yeast together with Aspergillus oryzae in koji making on the volatile compounds and quality of soy sauce moromi. Int J Food Sci Technol, 2015, 50(6): 1352-1358.

Liu XQ, Feng YL, Lai XH, . Virgibacillus halodenitrificans ST-1 for fermentation of shrimp paste and hydrolysates of its protease. Food Sci Nutr, 2020, 8(10): 5352-5361.

Liu XF, Lu Q, Xiao H, . Expression of a salt-tolerant pseudolysin in yeast for efficient protein hydrolysis under high-salt conditions. Biomolecules, 2023, 13(1): 83.

Madern D, Camacho M, Rodriguez-Arnedo A, . Salt-dependent studies of NADP-dependent isocitrate dehydrogenase from the halophilic archaeon Haloferax volcanii. Extremophiles, 2004, 8(5): 377-384.

Martinez R, Jakob F, Tu R, . Increasing activity and thermal resistance of Bacillus gibsonii alkaline protease (BgAP) by directed evolution. Biotechnol Bioeng, 2013, 110(3): 711-720.

Matkawala F, Nighojkar S, Kumar A, . Microbial alkaline serine proteases: production, properties and applications. World J Microbiol Biotechnol, 2021, 37(4): 63.

Mevarech M, Frolow F, Gloss LM, . Halophilic enzymes: proteins with a grain of salt. Biophys Chem, 2000, 86(2–3): 155-164.

Moghaddam JA, Boehringer N, Burdziak A, . Different strategies of osmoadaptation in the closely related marine myxobacteria Enhygromyxa salina SWB007 and Plesiocystis pacifica SIR-1. Microbiology-Sgm, 2016, 162: 651-661.

Mokashe N, Chaudhari B, Patil U, . Detergent-compatible robust alkaline protease from newly isolated halotolerant Salinicoccus sp. UN-12. J Surfactants Deterg, 2017, 20(6): 1377-1393.

Mokashe N, Chaudhari B, Patil U, . Operative utility of salt-stable proteases of halophilic and halotolerant bacteria in the biotechnology sector. Int J Biol Macromol, 2018, 117: 493-522.

Motamedi E, Motahar SFS, Maleki M, . Upgrading the enzymatic hydrolysis of lignocellulosic biomass by immobilization of metagenome-derived novel halotolerant cellulase on the carboxymethyl cellulose-based hydrogel. Cellulose, 2021, 28(6): 3485-3503.

Naveed M, Nadeem F, Mehmood T, . Protease-A versatile and ecofriendly biocatalyst with multi-industrial applications: an updated review. Catal Lett, 2021, 151(2): 307-323.

Nishikawa A, Senba H, Kimura Y et al (2022) Isolation and characterization of a salt-tolerant gamma-glutamyl transpeptidase from xerophilic Aspergillus sydowii. 3 Biotech 12(10):253.

Oren A, Mana L. Amino acid composition of bulk protein and salt relationships of selected enzymes of Salinibacter ruber, an extremely halophilic bacterium. Extremophiles, 2002, 6(3): 217-223.

Orhan E, Omay D, Guvenilir Y, . Partial purification and characterization of protease enzyme from Bacillus subtilis and Bacillus cereus. Appl Biochem Biotechnol, 2005, 121: 183-194.

Ortega G, Lain A, Tadeo X, . Halophilic enzyme activation induced by salts. Sci Rep-UK, 2011, 1: 6.

Ouelhadj A, Bouacem K, Asmani KL, . Identification and homology modeling of a new biotechnologically compatible serine alkaline protease from moderately halotolerant Gracilibacillus boraciitolerans strain LO15. Int J Biol Macromol, 2020, 161: 1456-1469.

Patipong T, Kageyama H, Waditee-Sirisattha R, . Insights into the phylogeny and transcriptional response of serine proteases in a halotolerant cyanobacterium Halothece sp. PCC7418. Plant Signal Behav, 2021, 16(9): e1913556.

Paul S, Bag SK, Das S, . Molecular signature of hypersaline adaptation: insights from genome and proteome composition of halophilic prokaryotes. Genome Biol, 2008, 9(4): R70.

Promchai R, Boonchalearn A, Visessanguan W, . Rapid production of extracellular thermostable alkaline halophilic protease originating from an extreme haloarchaeon, Halobacterium salinarum by recombinant Bacillus subtilis. Biocatal Agr Biotech, 2018, 15: 192-198.

Purohit MK, Singh SP. A metagenomic alkaline protease from saline habitat: cloning, over-expression and functional attributes. Int J Biol Macromol, 2013, 53: 138-143.

Qi W, Fan ZC, Wang CL, . Comparative study of physiological adaptation to salt stress in the genome shuffled Candida versatilis and a wild-type salt-tolerant yeast strain. Eur Food Res Technol, 2014, 238(4): 675-682.

Rahman MA, Culsum U, Kumar A, . Immobilization of a novel cold active esterase onto Fe₃O₄ similar to cellulose nano-composite enhances catalytic properties. Int J Biol Macromol, 2016, 87: 488-497.

Rao MB, Tanksale AM, Ghatge MS, . Molecular and biotechnological aspects of microbial proteases. Microbiol Mol Biol Rev, 1998, 62(3): 597-635.

Raval VH, Rathore DS, Singh SP, . Comparative studies of the characteristics of two alkaline proteases from Haloalkaliphilic bacterium D-15-9 and Oceanobacillus onchorynchii Mi-10-5₄. Appl Biochem Microbiol, 2022, 58(5): 551-563.

Razzaq A, Shamsi S, Ali A, . Microbial proteases applications. Front Bioeng Biotech, 2019, 7: 110.

Rodriguez-Rios M, Megia-Fernandez A, Norman DJ, . Peptide probes for proteases - innovations and applications for monitoring proteolytic activity. Chem Soc Rev, 2022, 51(6): 2081-2120.

Sana B, Ghosh D, Saha M, . Purification and characterization of a salt, solvent, detergent and bleach tolerant protease from a new gamma-Proteobacterium isolated from the marine environment of the Sundarbans. Process Biochem, 2006, 41(1): 208-215.

Senba H, Nishikawa A, Kimura Y, . Improvement in salt-tolerance of Aspergillus oryzae gamma-glutamyl transpeptidase via protein chimerization with Aspergillus sydowii homolog. Enzyme Microb Technol, 2023, 167.

Setyorini E, Takenaka S, Murakami S, . Purification and characterization of two novel halotolerant extracellular proteases from Bacillus subtilis strain FP-133. Biosci, Biotechnol, Biochem, 2006, 70(2): 433-440.

Shi WL, Tang XF, Huang YP, . An extracellular halophilic protease SptA from a halophilic archaeon Natrinema sp. J7: gene cloning, expression and characterization. Extremophiles, 2006, 10(6): 599-606.

Shirasaka N, Naitou M, Okamura K, . Purification and characterization of a fibrinolytic protease from Aspergillus oryzae KSK-3. Mycoscience, 2012, 53(5): 354-364.

Singh R, Chopra C, Gupta VK, . Purification and characterization of CHpro1, a thermotolerant, alkali-stable and oxidation-resisting protease of Chumathang hotspring. Sci Bull, 2015, 60(14): 1252-1260.

Singracha P, Niamsiri N, Visessanguan W, . Application of lactic acid bacteria and yeasts as starter cultures for reduced-salt soy sauce (moromi) fermentation. LWT-Food Sci Technol, 2017, 78: 181-188.

Sinha R, Khare SK. Structural changes in halophilic and non-halophilic proteases in response to chaotropic reagents. Protein J, 2014, 33(4): 394-402.

Sivaprakasam S, Dhandapani B, Mahadevan S, . Optimization studies on production of a salt-tolerant protease from Pseudomonas Aeruginosa strain BC1 and its application on tannery saline wastewater treatment. Braz J Microbiol, 2011, 42(4): 1506-1515.

Soppa J. From genomes to function: haloarchaea as model organisms. Microbiology-Sgm, 2006, 152: 585-590.

Stressler T, Ewert J, Merz M, . A novel glutamyl (Aspartyl)-specific aminopeptidase A from Lactobacillus delbrueckii with promising properties for application. PLoS ONE, 2016, 11(3

Sun JA, Li P, Liu Z, . A novel thermostable serine protease from a metagenomic library derived from marine sediments in the East China Sea. Appl Microbiol Biotechnol, 2020, 104(21): 9229-9238.

Tadeo X, Lopez-Mendez B, Trigueros T, . Structural basis for the amino acid composition of proteins from halophilic archea. PLoS Biol, 2009, 7(12

Takenaka S, Takada A, Kimura Y, . Improvement of the halotolerance of a Bacillus serine protease by protein surface engineering. J Basic Microbiol, 2022, 62(2): 174-184.

Takita T, Aono T, Sakurama H, . Effects of introducing negative charges into the molecular surface of thermolysin by site-directed mutagenesis on its activity and stability. Bba-Proteins Proteom, 2008, 1784(3): 481-488.

Tanasupawat S, Taprig T, Akaracharanya A, . Characterization of Virgibacillus strain TKNR13-3 from fermented shrimp paste (ka-pi) and its protease production. Afr J Microbiol Res, 2011, 5(26): 4714-4721.

Tang CH. Emulsifying properties of soy proteins: a critical review with emphasis on the role of conformational flexibility. Crit Rev Food Sci Nutr, 2017, 57(12): 2636-2679.

Tang J, Chen TT, Hu Q, . Improved protease activity of Pixian broad bean paste with cocultivation of Aspergillus oryzae QM-6 and Aspergillus niger QH-3. Electron J Biotechnol, 2020, 44: 33-40.

Vaidya S, Dev K, Sourirajan A, . Distinct osmoadaptation strategies in the strict halophilic and halotolerant bacteria isolated from lunsu salt water body of North West Himalayas. Curr Microbiol, 2018, 75(7): 888-895.

Vidyasagar M, Prakash S, Jayalakshmi SK, . Optimization of culture conditions for the production of halothermophilic protease from halophilic bacterium Chromohalobacter sp. TVSP101. World J Microbiol Biotechnol, 2007, 23(5): 655-662.

Vieille C, Zeikus GJ. Hyperthermophilic enzymes: Sources, uses, and molecular mechanisms for thermostability. Microbiol Mol Biol Rev, 2001, 65(1): 1-43.

Vreeland RH. Mechanisms of halotolerance in microorganisms. Crit Rev Microbiol, 1987, 14(4): 311-356.

Wahab WAA, Ahmed SA. Response surface methodology for production, characterization and application of solvent, salt and alkali-tolerant alkaline protease from isolated fungal strain Aspergillus niger WA 2017. Int J Biol Macromol, 2018, 115: 447-458.

Wang D, Zheng ZY, Feng J, . A high salt tolerant neutral protease from Aspergillus Oryzae: Purification, characterization and kinetic properties. Appl Biochem Microbiol, 2013, 49(4): 378-385.

Wang QY, Yang W, Pu SC, . Physicochemical properties of sufu produced by single and mixed fermentation with Mucor racemosus and Rhizopus oryzae. Curr Top Nutraceut R, 2020, 18(1): 63-69.

Wang FP, Li M, Huang L, . Cultivation of uncultured marine microorganisms. Mar Life Sci Tech, 2021, 3(2): 117-120.

Wang HJ, Liu HW, Yu Q, . A CPD photolyase gene PnPHR1 from Antarctic moss Pohlia nutans is involved in the resistance to UV-B radiation and salinity stress. Plant Physiol Biochem, 2021, 167: 235-244.

Wang SA, Zhang P, Xue YB, . Characterization of a novel aspartic protease from Rhizomucor miehei expressed in Aspergillus niger and its application in production of ACE-inhibitory peptides. Foods, 2021, 10(12): 2949.

Wei QZ, Wang HB, Chen ZX, . Profiling of dynamic changes in the microbial community during the soy sauce fermentation process. Appl Microbiol Biotechnol, 2013, 97(20): 9111-9119.

Wei MY, Chen PC, Zheng P, . Purification and characterization of aspartic protease from Aspergillus niger and its efficient hydrolysis applications in soy protein degradation. Microb Cell Fact, 2023, 22(1): 42.

Wu SM, Liu G, Zhang DC, . Purification and biochemical characterization of an alkaline protease from marine bacteria Pseudoalteromonas sp. 129–1. J Basic Microbiol, 2015, 55(12): 1427-1434.

Wu YW, Kameshwar AKS, Zhang B, . Genome and transcriptome analysis of rock-dissolving Pseudomonas sp. NLX-4 strain. Bioresour Bioprocess, 2022, 9(1): 63.

Xi Y, Ye LD, Yu HW, . Enhanced thermal and alkaline stability of L-lysine decarboxylase CadA by combining directed evolution and computation-guided virtual screening. Bioresour Bioprocess, 2022, 9(1): 24.

Xie L, Xiao YZ, Gao XY, . Purification and characterization of a halotolerant alkaline serine protease from Penicillium citrinum YL-1 isolated from traditional chinese fish sauce. Food Biotechnol, 2016, 30(2): 137-153.

Xie CZ, Zeng HY, Qin LK, . Physicochemical, taste, and functional changes during the enhanced fermentation of low-salt Sufu paste, a Chinese fermented soybean food. Int J Food Prop, 2018, 21(1): 2714-2729.

Yang HN, Liu Y, Ning YC, . Characterization of an intracellular alkaline serine protease from Bacillus velezensis SW₅ with fibrinolytic activity. Curr Microbiol, 2020, 77(8): 1610-1621.

Yang DQ, Li CS, Li LH, . Novel insight into the formation mechanism of umami peptides based on microbial metabolism in Chouguiyu, a traditional Chinese fermented fish. Food Res Int, 2022, 157.

Yin YQ, Xiao Y, Lin G, . An enzyme-inorganic hybrid nanoflower based immobilized enzyme reactor with enhanced enzymatic activity. J Mater Chem B, 2015, 3(11): 2295-2300.

Yue XQ, Li MH, Liu YM, . Microbial diversity and function of soybean paste in East Asia: what we know and what we don't. Curr Opin Food Sci, 2021, 37: 145-152.

Yuzuki M, Matsushima K, Koyama Y, . Expression of key hydrolases for soy sauce fermentation in Zygosaccharomyces rouxii. J Biosci Bioeng, 2015, 119(1): 92-94.

Zeng FF, Zhu YH, Zhang DL, . Metagenomic analysis of the soil microbial composition and salt tolerance mechanism in Yuncheng Salt Lake. Shanxi Province Front Microbiol, 2022, 13: 1004556.

Zhang H, Li H, Lang DA, . Purification, characterization and potential applications of a novel halotolerant metalloprotease from marine bacterium Vibrio sp LA-05. J Chem Technol Biotechnol, 2018, 93(12): 3627-3637.

Zhang H, Li H, Liu HR, . The application of a halotolerant metalloprotease from marine bacterium Vibrio sp. LA-05 in liquid detergent formulations. Int Biodeter Biodegr, 2019, 142: 18-25.

Zhang HW, Hu MK, Wang Q, . A novel salt-tolerant l-glutaminase: efficient functional expression, computer-aided design, and application. Fermentation-Basel, 2022, 8(9): 444.

Zhang XL, Liu ZP, Kang B, . Effect of Lactobacillus plantarum or Enterococcus faecalis as co-inoculants with Aspergillus oryzae in koji making on the physicochemical properties of soy sauce. J Food Sci, 2022, 87(2): 714-727.

Zhang Y, Guan FF, Xu GS, . A novel thermophilic chitinase directly mined from the marine metagenome using the deep learning tool Preoptem. Bioresour Bioprocess, 2022, 9(1): 54.

Zhang Y, Mao BY, Tang X, . Integrative genome and metabolome analysis reveal the potential mechanism of osmotic stress tolerance in Bifidobacterium bifidum. LWT-Food Sci Technol, 2022, 159.

Zhang Y, Hu JM, Zhang Q, . Enhancement of alkaline protease production in recombinant Bacillus licheniformis by response surface methodology. Bioresour Bioprocess, 2023, 10(1): 27.

Zhao HY, Feng H. Engineering Bacillus pumilus alkaline serine protease to increase its low-temperature proteolytic activity by directed evolution. BMC Biotechnol, 2018, 18: 34.

Zhao GZ, Hou LH, Lu MF, . Construction of the mutant strain in Aspergillus oryzae 3.042 for abundant proteinase production by the N plus ion implantation mutagenesis. Int J Food Sci Technol, 2012, 47(3): 504-510.

Zheng L, Chen SS, Xie LH, . Overexpression of cysteine protease gene from Salix matsudana enhances salt tolerance in transgenic Arabidopsis. Environ Exp Bot, 2018, 147: 53-62.

Zheng YF, Xu ZC, Liu HD, . Patterns in the microbial community of salt-tolerant plants and the functional genes associated with salt stress alleviation. Microbiol Spectr, 2021, 9(2

Zhou SQ, Zeng HY, Qin LK, . Screening of enzyme-producing strains from traditional Guizhou condiment. Biotechnol Biotec Eq, 2021, 35(1): 264-275.

Funding

National Natural Science Foundation of China(22138004); the first phase of the connotation construction of the 14th Five-Year Plan of Tibetan medicine(2021ZYYGH008)