Cultivation and diversity analysis of novel marine thraustochytrids

Thraustochytrids are a group of unicellular marine heterotrophic protists, and have long been known for their biotechnological potentials in producing squalene, polyunsaturated fatty acids (PUFAs) and other bioactive products. There are less than a hundred known strains from diverse marine habitats. Therefore, the discovery of new strains from natural environments is still one of the major limitations for fully exploring this interesting group of marine protists. At present, numerous attempts have been made to study thraustochytrids, mainly focusing on isolating new strains, analyzing the diversity in specific marine habitats, and increasing the yield of bioactive substances. There is a lack of a systematic study of the culturable diversity, and cultivation strategies. This paper reviews the distribution and diversity of culturable thraustochytrids from a range of marine environments, and describes in detail the most commonly used isolation methods and the control of culture parameters. Furthermore, the perspective approaches of isolation and cultivation for the discovery of new strains are discussed. Finally, the future directions of novel marine thraustochytrid research are proposed. The ultimate goal is to promote the awareness of biotechnological potentials of culturable thraustochytrid strains in industrial and biomedical applications.