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Sulfitobacter pseudonitzschiae H46, a marine bacterium associated with microalgae, exhibits algicidal activity against harmful algal bloom microalgae Chattonella marina and Alexandrium tamarense. The complete genome of S. pseudonitzschiae H46 was sequenced to investigate its algicidal mechanism further. One chromosome, eight circular plasmids and add one not circularized plasmid (Plas II) were identified, which are 4.93 Mb in length with 4871 open reading frames. The genome contains 43 transfer RNA (tRNA) genes; six ribosome RNA (rRNA) genes that can be classified into two 5S rRNA, two 16S rRNA, two 23S rRNA, and two small RNA (sRNA) genes. Genomic annotation revealed that S. pseudonitzschiae H46 has two pairs of LuxI/R-type Quorum-sensing (QS) systems. The QS systems can regulate the functions involved in host colonization and biofilm formation. Moreover, the existence of 49 Type-IV and Dddl genes in the chromosome indicated that Dimethylsulfoniopropionate (DMSP) catabolism of S. pseudonitzschiae H46 is the main interaction with marine microalgae. S. pseudonitzschiae H46 utilizes DMSP produced by microalgae as the carbon source, and this may induce algicidal activity. The complete genome sequence of S. pseudonitzschiae H46 can provide useful information on the underlying molecular mechanism between QS and algicidal activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • The roles of biochar on microbial growth and activity were systematically analyzed. • Biochar improved the microbial community diversity and population. • Biochar enhanced cellular enzyme activity and accelerated electron transfer. • Biochar promoted functional gene expression and regulated metabolic pathway. • Biochar targeted design to achieve high microbial activity in AD were suggested. The biochar is a well-developed porous material with various excellent properties, that has been proven with excellent ability in anaerobic digestion (AD) efficiency promotion. Current research is usually focused on the macro effects of biochar on AD, while the systematic review about the mechanisms of biochar on microbial behavior are still lacking. This review summarizes the effects and potential mechanisms of biochar on microorganisms in AD systems, and found that biochar addition can provide habitats for microbial colonization, alleviate toxins stress, supply essential nutrients, and accelerate interspecies electron transferring. Moreover, it also improves microbial community diversity, facilitates EPS secretion, enhances functional enzyme activity, promotes functional genes expression, and inhibits the antibiotic resistance genes transformation. Future research directions including biochar targeted design, in-depth microbial mechanisms revelation, and modified model development were suggested, which could promote the widely practical application of of biochar-amended AD technology. [ABSTRACT FROM AUTHOR]