2. Materials and methods
2.1. Pond bottom soil and organic sludge
Bottom soil samples from a 3-month-old pond were collected from a brackishwater shrimp farm in Chonburi Province, Thailand. Soil samples were collected in sterilized plastic bag and immediately transported to the laboratory and analyzed within 12 h. Organic sludge, referred to the soft fluidized, organic-rich residue, was collected from a post-harvested brackishwater shrimp farm in Chonburi Province. The organic sludge was collected in sterilized plastic bags and transported to the laboratory.