Anti-oxidative property of xylolipid produced by Lactococcus lactis LNH70 and its potential use as fruit juice preservative

• Published in: Brazilian journal of microbiology 2022-12, Vol.53 (4), p.2157-2172
• Main Authors: Nageshwar, L., Parameshwar, J., Rahman, Pattanathu K. S. M., Banat, Ibrahim M., Hameeda, Bee
• Format: Article
• Language: English
• Subjects: Ammonium; Ammonium sulfate; Antioxidants - analysis; Antioxidants - pharmacology; Bacteria; Biomedical and Life Sciences; Carbon sources; Chemical composition; Emulsification; Food; Food Microbiology; Food Microbiology - Research Paper; Fruit and Vegetable Juices; Fruit juices; Fruits; Juices; Lactic acid; Lactic acid bacteria; Lactococcus lactis; Lactococcus lactis - genetics; Lactose; Life Sciences; Medical Microbiology; Microbial Ecology; Microbial Genetics and Genomics; Microbiology; Microorganisms; Milk products; Mycology; Nitrogen; Optimization; Organic nitrogen; Oxidation-Reduction; Peptones; Phenols; Population studies; Preservatives; Probiotics; rRNA; Scavenging; Sequences; Sodium chloride; Sulfonic acid; Surface tension; Surfactants
• ISSN: 1517-8382; 1678-4405
• DOI: 10.1007/s42770-022-00837-8

In the present study, 20 lactic acid bacteria (LAB) were isolated from different fruit juices, milk, and milk products. Based on preliminary screening methods like emulsification index, oil displacement method, hemolysis, and reduction in surface tension, strain LNH70 was selected for further studies. Further, it was evaluated for preliminary probiotic characteristics, identified by 16 s rRNA sequencing as Lactococcus lactis , submitted to NCBI, and an accession number was obtained (MH174454). In addition, LNH70 was found to tolerate over wide range of temperatures (10–45 °C), pH (3–10), NaCl (up to 9%), bile (0.7%), and phenol (0.1%) concentrations. Further, optimization studies at flask level revealed that lactose as carbon source, peptone as organic nitrogen, and inorganic nitrogen (ammonium sulfate) enhanced biosurfactant production. Chemical composition of purified biosurfactant obtained from LNH70 was characterized by various physico-chemical analytical techniques and identified as xylolipid. Xylolipid biosurfactant exhibited anti-adhesion activity against food borne pathogens in in vitro conditions. Its anti-oxidative property by 1, 1-diphenyl-2-picrylhydrazyl (DPPH), 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS), and ferric reducing antioxidant power (FRAP) radical scavenging activity was found in range of 60.76 ± 0.5 to 83.50 ± 0.73%. Furthermore, xylolipid (0.05, 0.1, 0.3 mg/mL) when used for its potential as orange and pineapple juices preservation revealed miniature changes in the physico-chemical parameters evaluated in this study. However, the microbial population slightly lowered when xylolipid was used at 0.3 mg/mL after 5th day. Hence, this study supports the potential use of biosurfactant from L. lactis for its application as food preservative.