# Bacillus haimaensis sp. nov.: a novel cold seep-adapted bacterium with unique biosynthetic potential

## TL;DR

A new cold seep-adapted bacterium, Bacillus haimaensis, was discovered in the South China Sea, offering insights into deep-sea microbial adaptations and potential biotech uses.

## Contribution

The discovery of a novel Bacillus species with unique genomic features and biosynthetic potential in a deep-sea cold seep environment.

## Key findings

- Bacillus haimaensis has a 4.54 Mb genome with adaptations for cold seep environments, including enhanced nutrient acquisition and stress response mechanisms.
- The genome contains 27 unique gene clusters related to spore germination and sulfate assimilation, indicating specialized metabolic strategies.
- Six biosynthetic gene clusters, including a novel lassopeptide cluster, suggest potential for natural product discovery and bioremediation.

## Abstract

Deep-sea cold seeps harbor unique microbial communities that play crucial roles in biogeochemical cycles and possess potential biotechnological applications. Herein, we report the isolation, characterization, and genomic analysis of a novel Bacillus species, Bacillus haimaensis sp. nov. (type strain CSS-39T, CCTCC M20241382), obtained from sediments collected at a depth of 1,350 m in the Haima cold seep, South China Sea. Phylogenomic analysis, revealing an average nucleotide identity of 87.78% and a digital DNA-DNA hybridization value of 34.0% with its closest relative B. tianshenii DSM 25879T, confirms the taxonomic novelty of the genus Bacillus. The complete 4.54 Mb genome of B. haimaensis reveals adaptations to the cold seep environment, including enhanced nutrient acquisition capabilities and stress response mechanisms. Comparative genomic analysis identifies 27 unique gene clusters related to spore germination and sulfate assimilation, suggesting specialized metabolic strategies for this extreme habitat. Furthermore, six biosynthetic gene clusters, including a novel lassopeptide cluster, indicate a potential for secondary metabolite production. Phenotypic characterization demonstrates the strain’s ability to utilize diverse carbon sources and tolerate a wide range of environmental conditions. Our findings provide insights into microbial adaptations to deep-sea cold seeps and highlight the potential of B. haimaensis for biotechnological applications in bioremediation and natural product discovery. This study expands our understanding of microbial diversity in extreme marine environments and offers a new model bacterium for investigating bacterial adaptations to deep-sea ecosystems.

The discovery of Bacillus haimaensis sp. nov. in the Haima cold seep of the South China Sea represents a significant advancement in our understanding of microbial adaptations to extreme marine environments. This novel species exhibits remarkable metabolic versatility and unique genomic features, providing insights into bacterial survival strategies in nutrient-variable, high-pressure deep-sea ecosystems. Comprehensive genomic analysis reveals distinctive biosynthetic gene clusters, suggesting untapped potential for discovering novel natural product. Furthermore, B. haimaensis exhibits promising capabilities for aromatic compound degradation, indicating potential applications in marine bioremediation. This work not only expands our knowledge of microbial diversity in understudied deep-sea habitats but also highlights the biotechnological promise of extremophiles. The adaptive mechanisms elucidated in B. haimaensis, particularly those related to sporulation and sulfate assimilation, contribute to our broader understanding of microbial ecology in cold seeps and may inform future research on climate change impacts on deep-sea ecosystems.