**4.1 Sample collection**

Five hundred ml of water sample was collected from lake water from west campus at University Malaysia Sarawak (UNIMAS). The location was at latitude 1.468616 and longitude 110.430536. The samples obtained were stored in falcon tube and transported to the laboratory at room temperature (**Figure 3**).

### **4.2 Preparation of minimal salt media (MSM) broth and agar**

A standard formulation was used to prepare the Minimal Salt Media (MSM). All the chemical compounds were placed in 1 L conical flask after weighing using precision digital balance. Than the pH was adjusted to 7.2 0.2 at 25 °C. The chemical compounds used to prepare the media are as in the **Table 2**: Minimal Salt Media mixture;

The MSM double layer agar was prepared by adding 3 g of Bacto agar (Difco) into 200 ml prepared MSM broth in two conical flasks. Next, the MSM agar solution was autoclaved at 121 °C/15 atm for 1 hour and 30 minutes. Then, one of the conical flasks containing MSM agar solution was supplemented with 2 ml of 10X carbazole

**Figure 3.** *Location of sampling from a lake located at UNIMAS west campus, Sarawak.*
