Production of carotenoid sarcinaxanthin by Kocuria palustris isolated from Northeastern Brazil Caatinga soil and their antioxidant and photoprotective activities

Carotenoid pigments of Kocuria flava PUTS1_3 isolated from sediments of Puttalam lagoon mangrove ecosystem, Sri Lanka exhibit bioactive properties

Microorganisms, inhabiting various ecological niches, exhibit a capacity to produce a diverse array of pigments with different shades. These colorful microbial pigments may also potentially possess beneficial bioactivities. This dual functionality together with the ease of mass production and downstream processing has shifted the global attention towards the use of microbially-derived pigments as bioactive colorants in different industries. Therefore, the present study was conducted with the aim of characterizing the pigments from Kocuria flava and identifying their potential biotechnological applications. The bacterium, PUTS1_3, was isolated using the surface sediment samples from the Puttalam mangrove ecosystem, Sri Lanka and it was identified as Kocuria flava using 16S rRNA gene sequencing. The yellow, intracellular pigment of PUTS1_3 was obtained by treating the cell pellet with methanol. Characterization of the pigment extract using UV-visible spectroscopy, TLC, and HPLC confirmed the presence of three carotenoid compounds, including β-carotene. The pigment extract also demonstrated antibacterial activity, against Gram positive bacteria tested. Antioxidant properties were observed with an IC50 value of 181.95 ± 4.57 µg/ml in the DPPH free radical scavenging assay. Although its sun protection factor was comparatively low (SPF 7.69 ± 0.01), the pigment showed promising results as a textile dye demonstrating good color performance and stability in washing and pH stability tests. Moreover, fabrics dyed with the pigment extract displayed antibacterial activity against Staphylococcus aureus (ATCC 25923). These findings suggest the potential use of the yellow pigments of K. flava PUTS1_3 for various biotechnological applications.

Bioactive Metabolites from Radioresistant Bacterium Kocuria sp. TMM 11 and Their Role in Prevention of Ultraviolet-Induced Photodamages

A radioresistant bacterium identified as Kocuria sp.TMM 11 was isolated from Thal desert. Kocuria sp.TMM11 demonstrated resistance (57.3% survival rate) to an ultraviolet B radiations dose of 4.1 × 103 J/m2, 61.5% survival rate to hydrogen peroxide (60 mM) and 57.1% survivability to mitomycin C (6 μg/mL). An orange carotenoid pigment from strain TMM 11 was extracted using solvent mixture of methanol, ethyl acetate and acetone (7:5:3), subsequently purified using C18 cartridge column. The purified fraction was analyzed by liquid chromatography mass spectrometry and compounds identified were rhodovibrin, phytoene, 4'-Hydroxy-4,4'-diaponeurosporene-4-oic acid and 3,4,3',4'-Tetrahydrospirilloxanthin. The purified fraction with mixture of carotenoid compounds, was evaluated for its antioxidant activity, total flavonoids, phenolic content and radio protective potential. These assessments were conducted in relation to its ability to prevent protein and lipids oxidation, as well as DNA strand breaks in vitro. The fraction showed strong antioxidant activity, as indicated by its ability to scavenge super oxides, with an IC50 value of 50.8 μg/mL. Additionally, it displayed 75.76% iron chelation activity. The purified fraction strongly inhibited oxidative damage to proteins and lipids, comparable to the activity of standard ascorbic acid. The total phenolic and flavonoid contents in extract were measured 11.6 and 9.8 μg in terms of gallic acid and quercetin equivalents per milligram of dried mass. Hence, it is concluded that the carotenoid mixture from Kocuria sp.TMM 11 not only inhibited DNA strands from UV mediated photo damages but also protected lipid and protein peroxidation and therefore could be a good candidate in radio protective drugs and as sunscreen.

Enhanced UV-B photoprotection activity of carotenoids from the novel Arthrobacter sp. strain LAPM80 isolated from King George Island, Antarctica

Antarctica's harsh environmental conditions, characterized by high levels of ultraviolet (UV) radiation, pose challenges for microorganisms. To survive in these extreme cold regions with heightened UV exposure, microorganisms employ various adaptive strategies, including photoprotective carotenoid synthesis. Carotenoids are garnering attention in the skin health industry because of their UV photoprotection potential, given the direct relationship between UV exposure and skin burns, and cancer. Also, there is a growing demand for natural and environmentally friendly photoprotectors, such as microbial-based products, in opposition to synthetic photoprotective agents with known adverse effects. In this study, we assessed the carotenoid-producing abilities of Actinomycetota strains from Antarctic Peninsula soils and the photoprotective carotenoid action on UV irradiation resistance. Among 20 evaluated strains, one exhibited significant carotenoid production and it was identified through genomic analysis as a likely novel Arthrobacter sp. strain, LAPM80. This strain's genome revealed the presence of genes coding for the biosynthesis of decaprenoxanthin C50 carotenoid. The LAPM80 strain exhibited enhanced resistance against UV-B irradiation, correlating with increased total carotenoid production in its stationary growth phase. Chemical characterization of the carotenoid extract identified major components as C50 carotenoids, probably decaprenoxanthin and/or sarcinaxanthin. Scanning electron microscopy revealed minimal surface changes in bacteria during carotenoid-rich phase after UV-B irradiation exposure. These findings highlight the likely ability of LAPM80 strain's C50 carotenoids to improve UV-B iiradiation resistance, indicating their potential for developing natural photoprotective compounds for the dermo-cosmetic industry.

Hunting for pigments in bacterial settlers of the Great Pacific Garbage Patch

The Great Pacific Garbage Patch, a significant collection of plastic introduced by human activities, provides an ideal environment to study bacterial lifestyles on plastic substrates. We proposed that bacteria colonizing the floating plastic debris would develop strategies to deal with the ultraviolet-exposed substrate, such as the production of antioxidant pigments. We observed a variety of pigmentation in 67 strains that were directly cultivated from plastic pieces sampled from the Garbage Patch. The genomic analysis of four representative strains, each distinct in taxonomy, revealed multiple pathways for carotenoid production. These pathways include those that produce less common carotenoids and a cluster of photosynthetic genes. This cluster appears to originate from a potentially new species of the Rhodobacteraceae family. This represents the first report of an aerobic anoxygenic photoheterotrophic bacterium from plastic biofilms. Spectral analysis showed that the bacteria actively produce carotenoids, such as beta-carotene and beta-cryptoxanthin, and bacteriochlorophyll a. Furthermore, we discovered that the genetic ability to synthesize carotenoids is more common in plastic biofilms than in the surrounding water communities. Our findings suggest that plastic biofilms could be an overlooked source of bacteria-produced carotenoids, including rare forms. It also suggests that photoreactive molecules might play a crucial role in bacterial biofilm communities in surface water.

Functional profile and encapsulating properties of Colocasia esculenta (Taro)

Especially in tropical and subtropical countries, tuber and root crops have developed into important food crops. Due to its use in food preparation, aesthetics, and medicine, taro (Colocasia esculenta) is ranked as the fifth most important root crop. In comparison, it stores a considerable quantity of starch - even more than potatoes, sweet potatoes, cassava, and other similar crops. Colocasia leaves are lower in calories and high in dietary fiber minerals and proteins. The corms of Colocasia antiquorum contain anthocyanins such as pelargonidin-3-glucoside, cyanidin-3-glucoside, and cyanidin-3-chemnoside, which are reported to possess antifungal and antioxidative characteristics. The underground corms of taro (Colocasia esculenta), which contain 70%-80% starch, are the primary reason for its cultivation. Taro is a highly digestible root vegetable with a high content of mucilaginous gums and trivial starchy granules. It is used to make a variety of dishes. This review article highlights the functional properties, phytochemical profile, encapsulating properties, and various industrial applications. Its health advantages and dietary uses were also addressed.

Optimization and multiple in vitro activity potentials of carotenoids from marine Kocuria sp. RAM1

Marine pigmented bacteria are a promising natural source of carotenoids. Kocuria sp. RAM1 was isolated from the Red Sea Bohadschia graeffei collected from Marsa Alam, Egypt, and used for carotenoids production. The extracted carotenoids were purified by thin-layer chromatography (TLC). The characteristic UV absorbance of the three purified fractions gave us an inkling of what the purified pigments were. The chemical structures were confirmed by nuclear magnetic resonance spectroscopy (NMR) and LC-ESI-QTOF-MS/MS. The three different red pigments were identified as two C₅₀-carotenoids, namely bisanhydrobacterioruberin and trisanhydrobacterioruberin, in addition to 3,4,3',4'-Tetrahydrospirilloxanthin (C₄₂-carotenoids). Kocuria sp. RAM1 carotenoids were investigated for multiple activities, including antimicrobial, anti-inflammatory, antioxidant, anti-HSV-1, anticancer, antidiabetic and wound healing. These new observations suggest that Kocuria sp. RAM1 carotenoids can be used as a distinctive natural pigment with potent properties.

Metagenomic insights into the microbial community structure and resistomes of a tropical agricultural soil persistently inundated with pesticide and animal manure use

Persistent use of pesticides and animal manure in agricultural soils inadvertently introduced heavy metals and antibiotic/antibiotic resistance genes (ARGs) into the soil with deleterious consequences. The microbiome and heavy metal and antibiotic resistome of a pesticide and animal manure inundated agricultural soil (SL6) obtained from a vegetable farm at Otte, Eiyenkorin, Kwara State, Nigeria, was deciphered via shotgun metagenomics and functional annotation of putative ORFs (open reading frames). Structural metagenomics of SL6 microbiome revealed 29 phyla, 49 classes, 94 orders, 183 families, 366 genera, 424 species, and 260 strains with the preponderance of the phyla Proteobacteria (40%) and Actinobacteria (36%), classes Actinobacteria (36%), Alphaproteobacteria (18%), and Gammaproteobacteria (17%), and genera Kocuria (16%), Sphingobacterium (11%), and Brevundimonas (10%), respectively. Heavy metal resistance genes annotation conducted using Biocide and Metal Resistance Gene Database (BacMet) revealed the detection of genes responsible for the uptake, transport, detoxification, efflux, and regulation of copper, cadmium, zinc, nickel, chromium, cobalt, selenium, tungsten, mercury, and several others. ARG annotation using the Antibiotic Resistance Gene-annotation (ARG-ANNOT) revealed ARGs for 11 antibiotic classes with the preponderance of β-lactamases, mobilized colistin resistance determinant (mcr-1), macrolide-lincosamide-streptogramin (MLS), glycopeptide, and aminoglycoside resistance genes, among others. The persistent use of pesticide and animal manure is strongly believed to play a major role in the proliferation of heavy metal and antibiotic resistance genes in the soil. This study revealed that agricultural soils inundated with pesticide and animal manure use are potential hotspots for ARG spread and may accentuate the spread of multidrug resistant clinical pathogens.