Lactiplantibacillus plantarum tüvede võimekus sünteesida ekspolüsahhariide
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Kuupäev
2025
Kättesaadavus
05.09.2025
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Eksopolüsahhariidide (EPSide) süntees piimhappebakterite, sealhulgas Lactiplantibacillus plantarum, poolt on üha enam tähelepanu pälvinud nende võimalikule rakendusele toidu tekstuuri, viskoossuse, emulsioonide stabiilsuse ja sünereesi vähendamise parendamisel. Samas on mitmes uuringus täheldatud, et LABi poolt in situ toodetud EPSide kogused on sageli väikesed.
Bakalaureusetöö eesmärk oli välja selgitada, milline on L. plantarum tüvede (n=11) võimekus sünteesida eksopolüsahhariide. Eksperimentaalse osa käigus kasvatati L. plantarum tüvesid 2% sahharoosi lisandiga MRS söötmes, isoleeriti ja puhastati toodetud EPSid ning kvantifitseeriti need nii gravimeetrilise kui ka fenool-väävelhappe meetodi abil.
Tulemused näitasid, et EPSide glükoosiekvivalentne suhkrusisaldus jäi vahemikku 278,3 – 362,8 μg/mg ning tootlikkus 131,4 – 225,2 mg/L. Kõrgeim suhkrusisaldus tuvastati tüvel A44 ning suurim EPSide saagis aga tüvel A37. Statistiliselt olulisi erinevusi ei täheldatud ei suhkrusisalduse ega saagise osas, ei üksiktüvede ega genotüüpide lõikes (p>0,05). Küll aga ilmnesid erinevused lüofiliseeritud EPSide kuivmassis: G5 genotüüpi kuuluvate L. plantarum isolaatide A52 ja A45 puhul oli kuivmass statistiliselt oluliselt madalam võrreldes teiste genotüüpidega (p<0,05), välja arvatud G6-ga (isolaadid A51 ja A44), mille puhul erinevus ei olnud statistiliselt oluline. Samuti ei tuvastatud lineaarset korrelatsiooni suhkrusisalduse ja kuivmassi vahel (R² = 0,0177).
Kokkuvõttes näitasid kõik uuritud L. plantarum tüved võimet sünteesida EPSe märkimisväärsel tasemel. Edasised uuringud võiksid keskenduda L. plantarum tüvede kasvutingimuste (nt söötme koostis, pH, temperatuur, inkubatsiooniaeg ja lisandid) optimeerimisele, et suurendada EPSide tootlikkust ja võimaldada nende rakendamist toidutehnoloogilistes ja funktsionaalsetes toodetes.
The synthesis of exopolysaccharides (EPSs) by lactic acid bacteria (LAB), including Lactiplantibacillus plantarum, has gained increasing attention due to their potential applications in improving food texture, viscosity, emulsion stability, and reducing syneresis. However, several studies have reported that the amount of EPSs produced in situ by LAB is often low. The aim of this bachelor’s thesis was to determine the ability of L. plantarum strains (n=11) to synthesize EPSs. In the experimental part, the strains were cultivated in MRS medium supplemented with 2% sucrose, followed by EPS isolation and purification. Quantification was performed using both gravimetric analysis and the phenol–sulfuric acid method. The results showed that the total sugar content of EPSs ranged from 278.3 to 362.8 μg/mg, while the production yield varied from 131.4 to 225.2 mg/L. The highest sugar content was detected in strain A44, and the highest EPS yield was observed in strain A37. No statistically significant differences in sugar content or yield were found between individual strains or genotypes (p>0.05). However, significant differences were observed in the lyophilized EPS dry mass: isolates A52 and A45, belonging to genotype G5, exhibited significantly lower dry mass compared to other genotypes (p<0.05), except for genotype G6 (isolates A51 and A44), with which the difference was not statistically significant. No linear correlation was observed between sugar content and dry mass (R² = 0.0177). In conclusion, all investigated L. plantarum strains demonstrated the ability to synthesize EPSs at a considerable level. Future studies should focus on optimizing the cultivation conditions of L. plantarum strains (e.g., medium composition, pH, temperature, incubation time, and additives) to enhance EPS production and enable their application in food technology and functional food products.
The synthesis of exopolysaccharides (EPSs) by lactic acid bacteria (LAB), including Lactiplantibacillus plantarum, has gained increasing attention due to their potential applications in improving food texture, viscosity, emulsion stability, and reducing syneresis. However, several studies have reported that the amount of EPSs produced in situ by LAB is often low. The aim of this bachelor’s thesis was to determine the ability of L. plantarum strains (n=11) to synthesize EPSs. In the experimental part, the strains were cultivated in MRS medium supplemented with 2% sucrose, followed by EPS isolation and purification. Quantification was performed using both gravimetric analysis and the phenol–sulfuric acid method. The results showed that the total sugar content of EPSs ranged from 278.3 to 362.8 μg/mg, while the production yield varied from 131.4 to 225.2 mg/L. The highest sugar content was detected in strain A44, and the highest EPS yield was observed in strain A37. No statistically significant differences in sugar content or yield were found between individual strains or genotypes (p>0.05). However, significant differences were observed in the lyophilized EPS dry mass: isolates A52 and A45, belonging to genotype G5, exhibited significantly lower dry mass compared to other genotypes (p<0.05), except for genotype G6 (isolates A51 and A44), with which the difference was not statistically significant. No linear correlation was observed between sugar content and dry mass (R² = 0.0177). In conclusion, all investigated L. plantarum strains demonstrated the ability to synthesize EPSs at a considerable level. Future studies should focus on optimizing the cultivation conditions of L. plantarum strains (e.g., medium composition, pH, temperature, incubation time, and additives) to enhance EPS production and enable their application in food technology and functional food products.
Kirjeldus
Bakalaureusetöö
Toiduainete tehnoloogia õppekaval
Märksõnad
bakalaureusetööd, fenool-väävelhappemeetod, mikroobne polüsahhariid, paksendajad, biofunktsionaalsus