Lactic acid bacteria with antimicrobial, proteolytic and lipolytic activities isolated from ovine dairy products

Abstract This study aimed to isolate lactic acid bacteria from sheep milk products and to characterize these microorganisms with a focus on their antimicrobial, proteolytic and lipolytic activities. Raw milk, pasteurized milk, pasteurized cream, and butter samples were collected, lactic acid bacteria were isolated and their proteolytic, lipolytic and antimicrobial activities were evaluated. Lactic acid bacteria counts were higher in raw milk collected at the farm number 4 (8.91 ± 0.05 log CFU/mL), in which adequate hygienic practices were observed for pre- and post-milking. A total of 253 isolates were obtained, and among them 37 were lactic acid bacteria, where 19 showed some type of activity, most of which from raw milk. Among the isolates of lactic acid bacteria, 48.65% (n=18) showed proteolytic activity, 13.51% (n=5) lipolytic activity, 10.81% (n=4) showed both proteolytic and lipolytic activities, and only 2.70% (n=1) showed antimicrobial activity. Isolation of lactic acid bacteria with technological properties demonstrated their potential use as starter cultures in processing of fermented dairy products.

摘要 本研究旨在从羊乳制品中分离乳酸菌（Lactic Acid Bacteria），并围绕该类微生物的抗菌、蛋白水解与脂解活性开展表征分析。采集生乳、巴氏杀菌乳、巴氏杀菌稀奶油及黄油样品，分离乳酸菌并评估其蛋白水解、脂解及抗菌活性。4号农场采集的生乳样本中，乳酸菌总数最高，达(8.91 ± 0.05) log CFU/mL，该农场的挤奶前后卫生操作规范达标。本研究共获得253株分离菌株，其中37株为乳酸菌，19株展现出至少一种活性，且多数分离自生乳样本。在乳酸菌分离株中，48.65%（n=18）具有蛋白水解活性，13.51%（n=5）具有脂解活性，10.81%（n=4）同时具备蛋白水解与脂解活性，仅2.70%（n=1）展现出抗菌活性。本次分离得到的具备工艺应用特性的乳酸菌，具备作为发酵乳制品生产用发酵剂的潜在应用价值。