Purification of conchocelis of Neoporphyra haitanensis by the method of dominant Bacteria enrichment comprehensive treatment

Conchocelis is the sporophyte generation of Porphyra sensu lato, and free-living conchocelis is the main form used for preserving the germplasm. Avoiding microbial contamination caused by algal-associated bacteria (AAB) and ensuring the cleanliness of germplasm are important tasks for the preservation of Porphyra germplasm. In this study, we applied dominant bacteria enrichment comprehensive treatment (DBECT) to purify the conchocelis by enriching the dominant bacteria (Ruegeria scottomollicae S1) to occupy the niches of AAB and then remove them via antibiotics. The results showed that DBECT could efficiently remove AAB of Porphyra conchocelis germplasm, the abundance of which decreased 2000 times that of cultures treated with combined antibiotic cocktail methods. The diversity of AAB was reduced. In addition, adding R. scottomollicae S1 could adjust the community composition of algal microorganisms and increase the proportion of beneficial bacteria. Thus, DBECT can effectively purify Porphyra germplasm and provide ultra-clean algal samples for further research.