Marine Microbial-Derived Resource Exploration: Uncovering the Hidden Potential of Marine Carotenoids

Marine Carotenoids: Unlocking Advanced Antioxidant Mechanisms and Therapeutic Applications for Oxidative Stress

Marine ecosystems are a rich source of bioactive compounds, with carotenoids like astaxanthin, fucoxanthin, and zeaxanthin demonstrating significant antioxidant properties. These carotenoids neutralize reactive oxygen species (ROS), protecting against oxidative damage. This review examines their molecular structures, biosynthesis pathways, and mechanisms of action, including radical scavenging and involvement in key signaling pathways. Antioxidant assays confirm their potent ability to mitigate oxidative stress, with therapeutic implications for chronic diseases such as cancer, cardiovascular disorders, neurodegenerative diseases, and diabetes. Carotenoids also show promise in food, cosmetic, and nutraceutical applications, emphasizing the importance of sustainable sourcing. This review highlights the role of carotenoids in preventive health strategies and their potential to address oxidative stress-related diseases.

From the depths of the Java Trench: genomic analysis of Priestia flexa JT4 reveals bioprospecting and lycopene production potential

BACKGROUND

The marine environment boasts distinctive physical, chemical, and biological characteristics. While numerous studies have delved into the microbial ecology and biological potential of the marine environment, exploration of genetically encoded, deep-sea sourced secondary metabolites remains scarce. This study endeavors to investigate marine bioproducts derived from deep-sea water samples at a depth of 1,000 m in the Java Trench, Indonesia, utilizing both culture-dependent and whole-genome sequencing methods.

RESULTS

Our efforts led to the successful isolation and cultivation of a bacterium Priestia flexa JT4 from the water samples, followed by comprehensive genome sequencing. The resultant high-quality draft genome, approximately 4 Mb, harbored 5185 coding sequences (CDSs). Notably, 61.97% of these CDSs were inadequately characterized, presenting potential novel CDSs. This study is the first to identify the "open-type" (α < 1) pangenome within the genus Priestia. Moreover, our analysis uncovered eight biosynthetic gene clusters (BGCs) using the common genome mining pipeline, antiSMASH. Two non-ribosomal peptide synthetase (NRPS) BGCs within these clusters exhibited the potential to generate novel biological compounds. Noteworthy is the confirmation that the terpene BGC in P. flexa JT4 can produce lycopene, a compound in substantial industrial demand. The presence of lycopene in the P. flexa JT4 cells was verified using Ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) in multiple reaction modes.

CONCLUSIONS

This study highlights the bioprospecting opportunity to explore novel bioproducts and lycopene compounds from P. flexa JT4. It marks the pioneering exploration of deep-sea bacterium bioprospecting in Indonesia, seeking to unveil novel bioproducts and lycopene compounds through a genome mining approach.

Optimization, characterization and biosafety of carotenoids produced from whey using Micrococcus luteus

This study aimed to optimize the production of carotenoid pigments from Micrococcus luteus (ATCC 9341) through the statistical screening of media components and the characterization of antimicrobial, antioxidant, cytogenetic and cytotoxic activities. A BOX-Behnken design was used to assess the effects of whey concentration, inoculum size, pH, temperature, and agitation speed on carotenoid yield. The optimum combination increased production to 2.19 g/L, with a productivity of 0.045 g L-1 h-1 and a productivity yield of 0.644 g/g, as confirmed by an observed carotene production of 2.19 g/L. The final response surface model fitting the data had an R2 of 0.9461. High-performance liquid chromatography (HPLC) analysis identified 12 carotenoid pigment compounds produced by M. luteus. The extracts displayed moderate antimicrobial efficacy against Gram-positive bacteria such as Bacillus cereus (ATCC 11778), Staphylococcus aureus (ATCC 6538), and E. faecalis (ATCC 19433), with inhibition zone diameters (IZD) of 29.0, 14.0, and 37.0 mm, respectively, at 1000 μg/mL. However, its effectiveness against Gram-negative bacteria is limited. In comparison, tetracycline exhibited greater antimicrobial potency. The IC50 value of carotenoids was used to indicate the antioxidant activity. IC50 value from the DPPH assay was 152.80 mg/100mL. An IC50 cytotoxicity value greater than 300 μg/mL was found against normal mouse liver cells, with over 68% cell viability even at 300 μg/mL, indicating low toxicity. Histological structure studies revealed normal myocardial muscle tissue, lung tissue, and kidney tissue sections, whereas liver tissue sections revealed ballooning degeneration of hepatocytes and disorganization of hepatic cords. Cytogenetic parameters revealed that the carotene treatment group had a mitotic index (70%) lower than that of the control but higher than that of the positive control, mitomycin, and did not substantially increase numerical (1.2%) or structural aberrations compared with those of the control, suggesting a lack of genotoxic effects under the experimental conditions. In conclusion, optimized culture conditions enhanced carotenoid yields from M. luteus, and the extracts displayed promising bioactivity as moderate antibiotics against certain gram-positive bacteria and as antioxidants. The high IC50 values demonstrate biosafety. Overall, this bioprocess for enhanced carotenoid production coupled with bioactivity profiling and low cytotoxicity support the application of M. luteus carotenoids.

The unique epicuticular chemistry of Collembola - A cross-species analysis

Springtails (Collembola), tiny hexapod arthropods, are abundant in the soil of most ecosystems, but our knowledge of their secondary metabolites is limited, in contrast to that of insects. In insects, the outer cuticle is usually covered by mixtures of long-chain hydrocarbons serving different functions, such as water regulation or chemical communication. In contrast, the knowledge of the epicuticular chemistry of springtails is scarce. We analyzed the cuticular lipids of 23 species covering different lineages. The often complicated structures were elucidated using gas chromatography/mass spectrometry, microderivatization, and synthesis. In contrast to insects, the terpene biosynthetic pathway is used for many of these lipids, producing unprecedented higher terpenes. In addition, evidence for de novo cholesterol biosynthesis in springtails was found, which is absent in insects. Finally, diverse non-insect linear compounds originating from the fatty acid biosynthetic pathway were identified. Our comparative analysis showed clear differences compared to insects and shed light on phylogenetic relationships.

Blue Biotechnology: Marine Bacteria Bioproducts

The ocean is the habitat of a great number of organisms with different characteristics. Compared to terrestrial microorganisms, marine microorganisms also represent a vast and largely unexplored reservoir of bioactive compounds with diverse industrial applications like terrestrial microorganisms. This review examines the properties and potential applications of products derived from marine microorganisms, including bacteriocins, enzymes, exopolysaccharides, and pigments, juxtaposing them in some cases against their terrestrial counterparts. We discuss the distinct characteristics that set marine-derived products apart, including enhanced stability and unique structural features such as the amount of uronic acid and sulfate groups in exopolysaccharides. Further, we explore the uses of these marine-derived compounds across various industries, ranging from food and pharmaceuticals to cosmetics and biotechnology. This review also presents a broad description of biotechnologically important compounds produced by bacteria isolated from marine environments, some of them with different qualities compared to their terrestrial counterparts.

Metagenomic Analysis of Antarctic Ocean near the King Sejong Station Reveals the Diversity of Carotenoid Biosynthetic Genes

Carotenoids, biotechnologically significant pigments, play crucial biological roles in marine microorganisms. While various environments have been explored to understand the diversity of carotenoids and their biosynthesis, the Antarctic Ocean remains relatively under-investigated. This study conducted a metagenomic analysis of seawater from two depths (16 and 25 m) near the King Sejong Station in the Antarctic Ocean. The analysis revealed a rich genetic diversity underlying C40 (astaxanthin, myxol, okenone, spheroidene, and spirilloxanthin), C30 (diaponeurosporene, diapolycopene, and staphyloxanthin), and C50 (C.p. 450) carotenoid biosynthesis in marine microorganisms, with notable differential gene abundances between depth locations. Exploring carotenoid pathway genes offers the potential for discovering diverse carotenoid structures of biotechnological value and better understanding their roles in individual microorganisms and broader ecosystems.

Biosynthetic gene cluster profiling from North Java Sea Virgibacillus salarius reveals hidden potential metabolites

Virgibacillus salarius 19.PP.SC1.6 is a coral symbiont isolated from Indonesia's North Java Sea; it has the ability to produce secondary metabolites that provide survival advantages and biological functions, such as ectoine, which is synthesized by an ectoine gene cluster. Apart from being an osmoprotectant for bacteria, ectoine is also known as a chemical chaperone with numerous biological activities such as maintaining protein stability, which makes ectoine in high demand in the market industry and makes it beneficial to investigate V. salarius ectoine. However, there has been no research on genome-based secondary metabolite and ectoine gene cluster characterization from Indonesian marine V. salarius. In this study, we performed a genomic analysis and ectoine identification of V. salarius. A high-quality draft genome with total size of 4.45 Mb and 4426 coding sequence (CDS) was characterized and then mapped into the Cluster of Orthologous Groups (COG) category. The genus Virgibacillus has an "open" pangenome type with total of 18 genomic islands inside the V. salarius 19.PP.SC1.6 genome. There were seven clusters of secondary metabolite-producing genes found, with a total of 80 genes classified as NRPS, PKS (type III), terpenes, and ectoine biosynthetic related genes. The ectoine gene cluster forms one operon consists of ectABC gene with 2190 bp gene cluster length, and is successfully characterized. The presence of ectoine in V. salarius was confirmed using UPLC-MS/MS operated in Multiple Reaction Monitoring (MRM) mode, which indicates that V. salarius has an intact ectoine gene clusters and is capable of producing ectoine as compatible solutes.

A critical review of machine-learning for "multi-omics" marine metabolite datasets

During the last decade, genomic, transcriptomic, proteomic, metabolomic, and other omics datasets have been generated for a wide range of marine organisms, and even more are still on the way. Marine organisms possess unique and diverse biosynthetic pathways contributing to the synthesis of novel secondary metabolites with significant bioactivities. As marine organisms have a greater tendency to adapt to stressed environmental conditions, the chance to identify novel bioactive metabolites with potential biotechnological application is very high. This review presents a comprehensive overview of the available "-omics" and "multi-omics" approaches employed for characterizing marine metabolites along with novel data integration tools. The need for the development of machine-learning algorithms for "multi-omics" approaches is briefly discussed. In addition, the challenges involved in the analysis of "multi-omics" data and recommendations for conducting "multi-omics" study were discussed.

Sun protection and antibacterial activities of carotenoids from the soft coral Sinularia sp. symbiotic bacteria from Panjang Island, North Java Sea

Carotenoids have shown beneficial applications in cosmetology, pharmacology, and medicine. However, environmental stress in the marine environment can trigger the production of unique secondary metabolites, such as carotenoids. These compounds can also be sustainably produced by symbiotic bacteria. We hypothesized that the soft corals in tropical regions may produce diverse biological secondary metabolites, including carotenoids, both by the host organism and their bacterial symbiont. The unique carotenoids may provide promising biological activity such as antioxidant, UV photoprotector, and antibacterial activities. To this end, we isolated and characterized the carotenoids isolated from the bacterial symbiont of Sinularia sp., a soft coral from Panjang Island, North Java Sea, strain 19. PP.Sc.13. Bacterial identification was performed using DNA barcoding of the 16S rRNA region. Identification of carotenoids was carried out using a spectrophotometer, High-Performance Liquid Chromatography (HPLC), and attenuated total reflection fourier-transformed infrared (ATR-FTIR) spectroscopy. The antioxidant activity was estimated using the diphenylpicrylhydrazyl (DPPH) method, while the Sun Protection Factor (SPF) and % transmission of erythema and pigmentation were determined based on colorimetric methods. The antibacterial activity assay was carried out using the agar diffusion method against two multidrug-resistant bacteria. The bacterial symbiont was identified as Virgibacillus sp. and the carotenoids isolated from this symbiont exhibited significant antioxidant activity and extra sun protection effect, thus categorized as UVA sunblock. Furthermore, the isolated carotenoids exhibited antibacterial activities against Methicillin Resistant-Staphylococcus aureus (MRSA) and Multidrug-resistant (MDR) Escherichia coli. This study provides evidence of the carotenoids produced by the soft coral bacterial symbiont Virgibacillus sp., which may be used as an antioxidant, sun protection, and antibacterial agent. Further investigation of the de novo biological production of carotenoids by Virgibacillus sp. is warranted.