title: Actinopyga lecanora hydrolysates as natural antibacterial agents.
abstract: Actinopyga lecanora, a type of sea cucumber commonly known as stone fish with relatively high protein content, was explored as raw material for bioactive peptides production. Six proteolytic enzymes, namely alcalase, papain, pepsin, trypsin, bromelain and flavourzyme were used to hydrolyze A. lecanora at different times and their respective degrees of hydrolysis (DH) were calculated. Subsequently, antibacterial activity of the  A. lecanora hydrolysates, against some common pathogenic Gram positive bacteria (Bacillus subtilis and Staphylococcus aureus) and Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Pseudomonas sp.) were evaluated. Papain hydrolysis showed the highest DH value (89.44%), followed by alcalase hydrolysis (83.35%). Bromelain hydrolysate after one and seven hours of hydrolysis exhibited the highest antibacterial activities against Pseudomonas sp., P. aeruginosa and E. coli at 51.85%, 30.07% and 30.45%, respectively compared to the other hydrolysates. Protein hydrolysate generated by papain after 8 h hydrolysis showed maximum antibacterial activity against  S. aureus at 20.19%. The potent hydrolysates were further fractionated using RP-HPLC and antibacterial activity of the collected fractions from each hydrolysate were evaluated, wherein among them only three fractions from the bromelain hydrolysates exhibited inhibitory activities against Pseudomonas sp., P. aeruginosa and E. coli at 24%, 25.5% and 27.1%, respectively and one fraction of papain hydrolysate showed antibacterial activity of 33.1% against S. aureus. The evaluation of the relationship between DH and antibacterial activities of papain and bromelain hydrolysates revealed a meaningful correlation of four and six order functions.
authors.affiliation: Faculty of Food Science and Technology, University Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia. nazamid@putra.upm.edu.my.
authors.forename: Raheleh
authors.initials: R
authors.lastname: Ghanbari
authors.forename: Afshin
authors.initials: A
authors.lastname: Ebrahimpour
authors.forename: Azizah
authors.initials: A
authors.lastname: Abdul-Hamid
authors.forename: Amin
authors.initials: A
authors.lastname: Ismail
authors.forename: Nazamid
authors.initials: N
authors.lastname: Saari
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000187:drug effects / Q000502:physiology; D004926:Escherichia coli / Q000187:drug effects / Q000502:physiology; D006868:Hydrolysis; D008826:Microbial Sensitivity Tests; D010447:Peptide Hydrolases / Q000378:metabolism; D011492:Protein Hydrolysates / Q000494:pharmacology*; D011549:Pseudomonas / Q000187:drug effects / Q000502:physiology; D012616:Sea Cucumbers / Q000737:chemistry* / Q000378:metabolism; D013211:Staphylococcus aureus / Q000187:drug effects / Q000502:physiology
chemical_list: D000900:Anti-Bacterial Agents; D011492:Protein Hydrolysates; D010447:Peptide Hydrolases