Diversity of Carotenoid Pigmented Marine Photosynthetic Bacteria in the Dumai Sea Waters

¹ Marine Microbiology Laboratory, Department of Marine Science, Faculty of Fisheries and Marine Sciences, Riau University, 28293, Pekanbaru, Indonesia
² Chemical Oceanography Laboratory, Department of Marine Science, Faculty of Fisheries and Marine Sciences, Riau University, 28293, Pekanbaru, Indonesia

^* Corresponding author: ummimardhiah@lecturer.unri.ac.id

Abstract

Marine photosynthetic bacteria represent autotrophic microorganisms capable of synthesizing natural pigments. This study aims to explore the diversity of carotenoid-pigmented marine photosynthetic bacteria in the Dumai Sea waters, Riau Province, Indonesia. The research method was a survey using marine surface water as samples from six locations. The research was conducted in four primary phases: 1) measurement of environmental conditions; 2) enrichment and isolation of marine photosynthetic bacteria; 3) enumeration of total bacteria; and 4) analysis of pigments colour production. Isolation results and population density measurements of photosynthetic bacteria revealed fascinating patterns. The highest cell count was observed at fish auctions (sampling site 2), while the lowest cell count was recorded near a river estuary (sampling site 6). Detailed characterization studies identified ten isolates capable of producing natural carotenoid pigments exhibiting colours ranging from pink to deep red. These findings contribute to the understanding of marine microbial diversity and the potential of bacteria for biotechnology products, aquaculture, and medical applications.