Unveiling the Diversity and Enzymatic Potential of Cultivated Epiphytic Bacteria Isolated from Seaweeds

Seaweed surfaces harbor diverse epiphytic bacteria that are crucial for the health and development of their hosts. The present study explored the diversity and enzymatic production by the culturable epiphytic bacteria associated with green (Ulva lactuca and Halimeda opuntia), red (Amphiroa anceps), and brown (Sargassum wightii) seaweeds collected from the Mandapam coastal region, the southeast coast of India. Twenty-five bacterial isolates were identified by sequencing of the 16S rRNA gene and were found to belong to two common phyla, Firmicutes (17 isolates) and Proteobacteria (8 isolates, class Gammaproteobacteria), and four different families (Bacillaceae, Moraxellaceae, Pseudomonadaceae, and Halomonadaceae). In addition, the isolated bacteria were screened for the production of six enzymes such as agarase (EC 3.2.1.81), amylase (EC 3.2.1.1), cellulase (EC 3.2.1.4), gelatinase (EC 3.4.24.62), esterase (EC 3.1.1.1), and proteinase (EC 3.4.21). Twenty (80%) of the isolates had the capability to produce at least one of these hydrolytic enzymes, among which amylase and protease were the most common, as detected in 14 (56%) isolates. Gelatinase and esterase were produced, in only seven (28%) and six (24%) isolates, respectively. Moreover, the isolate Stutzerimonas balearica has been reported for the first time from India in this study. Our results indicate that this isolate is a bacterium promising in the search for enzymes of marine origin and for potential biotechnological application.