2.1. Preparation of axenic cultures
Healthy and disease-free commercially sea farm cultivated G. changii seaweed were collected from Semporna, Sabah and immediately transferred to Biotechnology Research Institute, Universiti Malaysia Sabah. Upon arrival, the samples were cleaned to remove epiphytic algae and rinsed with autoclaved seawater. Surface sterilization was carried out according to Yong et al. (2014a). The samples were incubated in an antibiotic solution: 100 mg L−1 penicillin G and 100 mg L−1 streptomycin sulfate in 50% of Provasoli’s enriched seawater (PES) medium ( Provasoli, 1968) for 48 h. The samples were then washed with 3.0 g L−1 povidone iodine and 15% ethanol for 30 s, followed by rinsing with autoclaved seawater. The seaweed was segmented into 10 cm in length and placed in a photobioreactor developed according to Yong et al. (2014a) with autoclaved seawater under a photoperiod of 12 h and temperature of 25 ± 1 °C.2. Materials and methods