Amajor, J.U* and Amajor, E .E. DOWNLOAD PDF


The study aimed to isolate and characterize from the fermenting newly bred yellow cassava dough by PCR-based molecular methods to identify the isolates to species level which cloud facilitate to formulate starter cultures and help in the preservation of foods. The yellow cassava dough was fermented and 30 isolates were isolated during fermentation at different stages at National Root Crops Research Instutite, Umudike. Methodology: The lactic acid bacteria isolates were selected on the basis of positive to acid production,(Gram stain reaction- positive, Catalase-negative, Oxidase- negative, Cell form- rod shaped). PCR- based molecular methods were used to identify the LAB isolates. A total of 30 lactic acid bacteria (LAB) isolates were obtained from fermenting dough of the newly bred yellow cassava and characterized at species level. The DNA of the bacterial isolates were extracted using ZYMO KIT (zymo research group California, U.S.A). 16s rRNA of the isolates were amplified using primiers 27F and 1492R and the amplified product sequenced at Ingaba Biotech West Africa (IBWA) South Africa. Sequence analysis were compared within the resource at database and were carried out to identify the isolated microorganism. The result showed 30 isolates and 10 each group of LAB. They were identified as LAB with rod shaped cell forms, Gram stain- positive, oxidase-negative, glucose- positive and negative and positive acid production. The 16s rRNA gene sequencing showed all the isolates. The bacterial LAB isolates were identified as  Lactobacillus brevis , Lactobacillus plantarum  and Lactobacillus fermentum with similarity index of 100%. The indigenous LAB of newly bred yellow cassava dough cloud be a potential source of starter cultures and biological preservation of food.

Key Words: Fermented dough; yellow cassava; Lactic acid bacteria; PCR; 16s rRNA gene; phylogenetic tree.