The diversity of actinobacteria associated with marine ascidian Phallusia nigra from Andaman Islands was investigated. A total of 10 actinobacteria were isolated and based on the biochemical and molecular characterization, the isolates were assigned to 7 different actinobacterial genera. Eight putatively novel species belonging to genera Rhodococcus, Kineococcus, Kocuria, Janibacter, Salinispora and Arthrobacter were identified based on 16S rDNA sequence similarity with the NCBI database. The organic extracts of ten isolates displayed considerable bioactivity against test pathogens, which were Gram-positive and Gram-negative in nature. PCR-based screening for type I and type II polyketide synthases (PKS-I, PKS-II) and nonribosomal peptide synthetases (NRPS) revealed that, 10 actinobacterial isolates encoded at least one type of polyketide synthases biosynthesis gene. Majority of the isolates found to produce industrially important enzymes; amylase, protease, gelatinase, lipase, DNase, cellulase, urease, phosphatase and l-asparaginase. The present study emphasized that, ascidians are a prolific resource for novel bioactive actinobacteria with potential for novel drug discovery. This result expands the scope to functionally characterize the novel ascidian associated marine actinobacteria and their metabolites could be a source for the novel molecules of commercial interest.

调查了与来自安达曼群岛的海鞘海鞘Phallusia nigra相关的放线菌的多样性。共分离出 10 种放线菌，并根据生化和分子特征，将分离物归为 7 个不同的放线菌属。八属于推定属新种红球菌，Kineococcus，Kocuria，Janibacter，Salinispora和节根据与 NCBI 数据库的 16S rDNA 序列相似性来鉴定。十个分离物的有机提取物对测试病原体表现出相当大的生物活性，这些病原体本质上是革兰氏阳性和革兰氏阴性。基于 PCR 的 I 型和 II 型聚酮合酶（PKS-I、PKS-II）和非核糖体肽合成酶 (NRPS) 的筛选表明，10 个放线菌分离株编码至少一种类型的聚酮合酶生物合成基因。大多数分离株被发现产生工业上重要的酶；淀粉酶、蛋白酶、明胶酶、脂肪酶、脱氧核糖核酸酶、纤维素酶、脲酶、磷酸酶和l-天冬酰胺酶。本研究强调，海鞘是具有新药发现潜力的新型生物活性放线菌的丰富资源。这一结果扩大了对新型海鞘相关海洋放线菌进行功能表征的范围，它们的代谢物可能是具有商业价值的新型分子的来源。