Optimization of Growth Media for Halophilic Bacteria Isolate from Salt Pond: A Kinetic Analysis Across Different Agar Substrates

Document Type : Original Article

Authors

1 Doctoral Program of Fisheries and Marine Science, Faculty of Fisheries and Marine Science, Brawijaya University, Malang 65145, Indonesia; Coastal and Marine Research Center Brawijaya University, Brawijaya University, Malang 65145, Indonesia

2 Department marine Science, faculty Fisheries and Marine Science, Universitas Brawijaya

3 Department of Aquaculture, Faculty of Fisheries and Marine Science, Brawijaya University Malang 65145, Indonesia

4 Department of Aquatic Resources Management, Brawijaya University

5 Aquaculture Study Program, Faculty of Fisheries and Marine Science, Universitas Brawijaya, Malang, Indonesia

6 Doctoral Program of Fisheries and Marine Sciences, Faculty of Fisheries and Marine Sciences, University of Brawijaya, Malang 65145, Indonesia

7 Department of Aquatic Resources Management, University of Brawijaya

10.21608/ejabf.2025.433301.6812

Abstract

Halophilic bacteria are extremophilic microorganisms with significant ecological and industrial importance, particularly for biotechnological applications such as enzyme production, bioremediation, and saline wastewater treatment. This study aimed to optimize culture media to enhance halophilic bacterial growth performance by evaluating four agar-based substrates with different nutrient compositions: Nutrient Agar  Modified (NAM), Mannitol Salt Agar (MSA), Total Plate Agar Modified (TPAM), and Casein Medium Agar (CMA). The bacterial isolate, obtained from hypersaline salt ponds (40% salinity) in East Java, Indonesia, was cultured for seven days under controlled laboratory conditions. Growth was quantified daily using colony-forming unit (CFU) counts, and kinetic parameters including maximum abundance (Y_max), specific growth rate (µ_max), generation time (g), and cumulative growth momentum (AUC-µ) were analyzed. The results revealed that CMA produced the highest growth rate (µ_max = 0.27 day⁻¹), the shortest generation time (g = 2.56 days), and the greatest overall growth momentum (AUC-µ = 0.436), indicating efficient nitrogen assimilation and rapid cell division under hypersaline stress. In contrast, MSA exhibited the slowest growth (µ_max = 0.06 day⁻¹) and longest generation time (g = 11.9 days). These findings confirm that medium composition strongly influences halophilic bacterial kinetics through nutrient assimilation and osmotic adaptation. Casein-based formulations such as CMA may therefore serve as a baseline medium for halophilic enzyme production and saline bioprocess development.

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