Characterization and growth profile of proteolytic strain PK-4 isolated from local slaughterhouse wastewater

¹ Faculty of Animal Science, Universitas Gadjah Mada, Jl. Fauna No.3 Bulaksumur, Yogyakarta, 55281, Indonesia

^* Corresponding author: nanungagusfitriyanto@ugm.ac.id

Abstract

This study aims to characterize and to determine the growth profile of the proteolytic bacteria isolated from Giwangan slaughterhouse wastewater in Yogyakarta City, and to observe the optimum temperature as well as the pH condition for growing in the nutrient medium. Isolation of bacteria from slaughterhouse wastewater was done with a sample from 4 different locations. The isolates were then grown on a medium with a skim (at 0;0.5;1%;1.5 and 2%) and pH condition (at 7;8;9;10 and 11). The bacterial growth profile was measured based on the number of cells (CFU/mL), the size of the bacterial colony diameter, the diameter of the clear zone, and the proteolytic index. Strain PK4 was proved to have proteolytic activity. The characterization of Strain PK4 has shown for colony morphology with a circle shape, white color, flat edges, and convex elevation. The cell morphology was a cocci-shaped, red color, Gram-negative, and having a catalase-positive. The bacterial colony diameter, halo diameter, and proteolytic index were increased significantly (P<0.05) with the increase of skim milk addition. The optimal growth at the medium has reached by the addition of 1–2 % Skim and pH alkaline (>7). It could be concluded that Strain PK4 was classified as alkalophilic and had the potency as alkaline protease producing bacteria.