Adnan Alkazah(1)*, Abdulwahab Meri(2) and Bassam Aloklah(3)
(1). Laboratory of the directorate of internal trade and consumer protection in the Damascus countryside
(2). Food Science Department-Faculty of Agriculture-Damascus University-Damascus-Syria
(3). National Commission for Biotechnology-Damascus-Syria
(*Corresponding author: Adnan Alkazah: adnankaza@hotmail.com, Mobile 0938291015)
Received: 30/5/2025 Accepted: 3/8/2025
Abstract:
Lactic acid is considered one of the most important organic acids due to its uses in food and industrial fields. The current research aimed to isolate lactic acid producing bacteria from different foodstuffs such as pickles (turnip, cucumber and capsicum), cheeses (Okawi and shelal), yoghurt, eyran, milk (bovine and sheep milk), Labaneh, Shanklish and keshek, and to choose the better isolate for using in lactic acid production on a medium based on cheese whey. The primary tests are performed on isolates, which include Gram stain and catalase test to ensure whether the isolated bacteria are Gram-positive (either they were cocci or bacilli) and catalase negative, so they are belonging to lactic acid bacteria group. The total number of samples was 79 and the total number of lactic acid bacteria was 60, the bacilli were 18 isolates and the cocci were 42 isolates. Whey samples were collected from Damascus, and they were tested for the percent of dry matter, fat, lactose, total ash, total acidity and pH value. The whey sample was prepared by protein precipitation for screening experiments, which performed on lactic acid bacteria that obtained from food samples, and aimed to identify the most effective isolate in producing lactic acid bacteria from cheese whey. The isolate Y7 produced the largest amount of lactic acid (28.12 g/L). The biochemical tests were performed for identifying this isolate by means of API 50 CHL strip, and this isolate found to be belonging to Lactobacillus paracasei. The identifying of the former isolate was confirmed by real time polymerase chain reaction (RT-PCR) technique, using specific primers designed based on the National Bank for Bioinformatics (NCBI), and this technique ensured the accuracy of the identification using API 50 CHL strip, and that the superior isolate Y7 is belonging to Lactobacillus paracasei.
Keywords: API 50 CHL strip, cheese whey, lactic acid, Lactobacillus paracasei, RT-PCR technique.
Full paper in Arabic: PDF