Exploring the fermentation characteristics of a newly isolated marine bacteria strain, Gordonia terrae TWRH01 for carotenoids production

Ketocarotenoids adonirubin and adonixanthin: Properties, health benefits, current technologies, and emerging challenges

Given their multifaceted roles, carotenoids have garnered significant scientific interest, resulting in a comprehensive and intricate body of literature that occasionally presents conflicting findings concerning the proper characterization, quantification, and bioavailability of these compounds. Nevertheless, it is undeniable that the pursuit of novel carotenoids remains a crucial endeavor, as their diverse properties, functionalities and potential health benefits make them invaluable natural resources in agri-food and health promotion through the diet. In this framework, particular attention is given to ketocarotenoids, viz., astaxanthin (one of them) stands out for its possible multifunctional role as an antioxidant, anticancer, and antimicrobial agent. It has been widely explored in the market and utilized in different applications such as nutraceuticals, food additives, among others. Adonirubin and adonixanthin can be naturally found in plants and microorganisms. Due to the increasing significance of natural-based products and the remarkable opportunity to introduce these ketocarotenoids to the market, this review aims to provide an expert overview of the pros and cons associated with adonirubin and adonixanthin.

Optimized carotenoid production and antioxidant capacity of Gordonia hongkongensis

The current emphasis within the cosmetic market on sustainable ingredients has heightened the exploration of new sources for natural, active components. Actinomycetota, recognized for producing pigments with bioactive potential, offer promising functional cosmetic ingredients. This study aimed to optimize pigment and antioxidant metabolite production from the Gordonia hongkongensis strain EUFUS-Z928 by implementing the Plackett-Burman experimental design and response surface methodology. Extracts derived from this strain exhibited no cytotoxic activity against human primary dermal fibroblast (HDFa, ATCC® PCS-201-012™, Primary Dermal Fibroblast; Normal, Human, Adult). Eight variables, including inoculum concentration, carbon and nitrogen source concentration, NaCl concentration, pH, incubation time, temperature, and stirring speed, were analyzed using the Plackett-Burman experimental design. Subsequently, factors significantly influencing pigment and antioxidant metabolite production, such as temperature, inoculum concentration, and agitation speed, were further optimized using response surface methodology and Box-Behnken design. The results demonstrated a substantial increase in absorbance (from 0.091 to 0.32), DPPH radical scavenging capacity (from 27.60% to 84.61%), and ABTS radical scavenging capacity (from 17.39% to 79.77%) compared to responses obtained in the isolation medium. The validation of the mathematical model accuracy exceeded 90% for all cases. Furthermore, liquid chromatography coupled with mass spectrometry (LC-MS) facilitated the identification of compounds potentially responsible for enhanced pigment production and antioxidant capacity in extracts derived from G. hongkongensis. Specifically, six carotenoids, red-orange pigments with inherent antioxidant capacity, were identified as the main enhanced compounds. This comprehensive approach effectively optimized the culture conditions and medium of a G. hongkongensis strain, resulting in enhanced carotenoid production and antioxidant capacity. Beyond identifying bioactive compounds and their potential cosmetic applications, this study offers insights into the broader industrial applicability of these extracts. It underscores the potential of G. hongkongensis and hints at the future utilization of other untapped sources of rare actinomycetes within the industry.

Isolation and identification of the alga-symbiotic bacterium Gordonia and characterisation of its exopolysaccharide

An exopolysaccharide (EPS)-producing bacterium TD18, isolated from the culture broth of green alga Scenedesmus obliquus, was identified as Gordonia terrae based on the 100% identity of 16S rRNA sequences and designated Gordonia terrae TD18. The results of compositional and structural analyses and physiochemical tests show that (1) the exopolysaccharide produced by G. terrae TD18 (TD18-EPS) is an acidic hetero-polysaccharide with a molecular weight of 23 kDa, consisting of glucose, mannose, galactose and glucuronic acid, and (2) TD18-EPS is of high thermal stability with a degradation temperature of 308 °C, the solution of which is non-Newtonian pseudoplastic fluid exhibiting good emulsifying properties over a wide range of temperatures, pH and NaCl concentrations. Hence, Gordonia terrae TD18 is the first alga-symbiotic Gordonia strain identified thus far, while TD18-EPS is unique in terms of composition and structure, different from the known Gordonia EPS, with excellent physiochemical properties and thus has potential applications in industry.

Bacteria as biofactory of pigments: Evolution beyond therapeutics and biotechnological advancements

Bacterial pigments are the wonder molecules of nature that have attracted the attention of industries in recent years. To date, various synthetic pigments have been in use in food, cosmetics, and textile industries that have not only shown a notoriously toxic nature but also posed threat to the ecosystem. Moreover, nutraceuticals, fisheries, and animal husbandry were highly dependent on plant sources for products that aid in disease prevention and improve stock health. In this context, the use of bacterial pigments as new-generation colorants, food fortifiers, and supplements can hold great prospects as low-cost, healthy, and eco-friendly alternatives. The majority of studies on these compounds were restricted to antimicrobial, antioxidant, and anticancer potentials to date. Each of these can be highly beneficial for the development of new-generation drugs, but their other potential niche in various industries that pose health and environmental risks needs to be explored. Recent advances in novel strategies of metabolic engineering, advancements in optimization tools for the fermentation process, and the design of appropriate delivery systems will greatly expand the market of bacterial pigments in industries. This review summarizes the current technologies for enhancing production, recovery, stability, and appreciable use of bacterial pigments in industries apart from therapeutics with proper financial aspects. The toxicity perspectives have been focused to emphasize that these wonder molecules are the need of the hour and their future prospects have been highlighted. Extensive literature has been studied to include the challenges of bacterial pigments from environmental and health risk perspectives.

Methods of Identifying Gordonia Strains in Clinical Samples

Gordonia spp. are members of the family Gordoniacea in the suborder Corynebacteriales; their habitat, in most cases, is soil. Many representatives of this genus are human or veterinary pathogens. The main cause of the lack of a standardized approach to dealing with infections caused by Gordonia is their erroneous identification and little information regarding their susceptibility to antimicrobial drugs. This review presents the most common methods for identifying Gordonia strains, including modern approaches for identifying a species. The main prospects and future directions of this field of knowledge are briefly presented.

Characterization and Bioactive Potential of Carotenoid Lutein from Gordonia rubripertncta GH-1 Isolated from Traditional Pixian Douban

The characterization and bioactive properties of carotenoid produced by Gordonia rubripertincta GH-1 originating from Pixian Douban (PXDB), the Chinese traditional condiment, was investigated. The produced and purified yellow pigment was characterized by ultraviolet-visible spectroscopy (UV-Vis), Fourier transformed infrared (FTIR), nuclear magnetic resonance (NMR), and high-resolution mass spectrometry (HRMS), and was identified as carotenoid lutein. Additionally, the bioactive activity of lutein from G. rubripertincta GH-1 was evaluated by measuring the free radical scavenging capacity in vitro and feeding zebrafish lutein through aqueous solution. The results showed that the carotenoid lutein had strong antioxidant capacity and a protective effect on zebrafish eye cells, which could inhibit the apoptosis of eye cells in a concentration dependent manner. The results suggested that carotenoid lutein from G. rubripertincta GH-1 could be utilized as a potential source of natural antioxidants or functional additives for food/pharmaceutical industries.

Micrococcus lylae MW407006 Pigment: Production, Optimization, Nano-Pigment Synthesis, and Biological Activities

Simple Summary

The global crisis of increased mortality rates due to the emergence of antimicrobial resistance and cancers has increased researchers’ efforts to find new, potent solutions through implementing natural products in the pharmaceutical industry. The present investigation produced echinenone (yellowish-orange pigment) from Micrococcus lylae MW407006 with potent pharmacological activities. A response surface methodology statistical design was used to optimize the biomass production, pigment concentration, and antimicrobial activity. The Spearman correlation coefficient was assessed, which indicated a strong linear relationship between biomass production, pigment concentration, and antimicrobial activity. Nano-echinenone was physically synthesized through the ball-milling technique. The synthesized nano-echinenone showed higher pharmacological activities (antimicrobial, antioxidant, and antitumor activities) in comparison with the crude pigment. The significantly high selectivity index of the synthesized nano-echinenone proved its safety and paved the way for its possible use in the pharmaceutical industry.

Abstract

Bacterial pigments (e.g., melanin and carotenoids) are considered to be among the most important secondary metabolites due to their various pharmacological activities against cancer and microbial resistance. Different pigmented bacterial strains were isolated from soil samples from El Mahmoudiyah governance and screened for their antimicrobial activity. The most promising pigment producer was identified as Micrococcus lylae MW407006; furthermore, the produced pigment was identified as echinenone (β-carotene pigment). The pigment production was optimized through a central composite statistical design to maximize the biomass production, pigment concentration, and the antimicrobial activity. It was revealed that the most significant fermentation parameters were the glucose (as a carbon source) and asparagine (as a nitrogen source) concentrations. Nano-echinenone was synthesized using the ball milling technique, characterized, and finally assessed for potential antimicrobial, antioxidant, and antitumor activities. The data revealed that the synthesized nano-echinenone had higher antimicrobial activity than the crude pigment. The cytotoxic potency of echinenone and nano-echinenone was investigated in different cell lines (normal and cancer cells). The inhibition of cell proliferation and induction of cell death was observed in Caco-2 and Hep-G2 cells. The data proved that nano-echinenone is a suitable candidate for use as a safe antimicrobial and anti-hepatocellular-carcinoma agent.

Cliona varians-Derived Actinomycetes as Bioresources of Photoprotection-Related Bioactive End-Products

Sunscreen and sunblock are crucial skincare products to prevent photoaging and photocarcinogenesis through the addition of chemical filters to absorb or block ultraviolet (UV) radiation. However, several sunscreen and sunblock ingredients, mostly UV filters, have been associated with human and environmental safety concerns. Therefore, the exploration and discovery of promising novel sources of efficient and safer compounds with photoprotection-related activities are currently required. Marine invertebrates, particularly their associated microbiota, are promising providers of specialized metabolites with valuable biotechnological applications. Nevertheless, despite Actinobacteria members being a well-known source of bioactive metabolites, their photoprotective potential has been poorly explored so far. Hence, a set of methanolic extracts obtained from Cliona varians-derived actinomycetes was screened regarding their antioxidant and UV-absorbing capacities (i.e., photoprotection-related activities). The active extract-producing strains were identified and classified within genera Streptomyces, Micrococcus, Gordonia, and Promicromonospora. This is the first report of the isolation of these microorganisms from C. varians (an ecologically important Caribbean coral reef-boring sponge). The in vitro cytotoxicity on dermal fibroblasts of oxybenzone and the selected active extracts revealed that oxybenzone exerted a cytotoxic effect, whereas no cytotoxic effect of test extracts was observed. Accordingly, the most active (SPFi > 5, radical scavenging > 50%) and nontoxic (cell viability > 75%) extracts were obtained from Streptomyces strains. Finally, LC-MS-based characterization suggested a broad chemical space within the test strains and agreed with the reported streptomycetes' chemodiversity. The respective metabolite profiling exposed a strain-specific metabolite occurrence, leading to the recognition of potential hits. These findings suggest that marine Streptomyces produce photoprotectants ought to be further explored in skincare applications.

Microbial pigments as an alternative to synthetic dyes and food additives: a brief review of recent studies

Synthetic coloring agents have been broadly utilized in several industries such as food, pharmaceuticals, cosmetic and textile. Recent surveys on the potential of teratogenicity and carcinogenicity of synthetic dyes have expressed concerns regarding their use in foods. Worldwide, food industries have need for safe, natural and new colorings to add variety to foods and make them appealing to consumers. Natural colorings not only expand the marketability of the food product, but also add further healthful features such as antibacterial, antioxidant, anticancer and antiviral properties. Novel microbial strains should be explored to meet the increasing global search of natural pigments and suitable techniques must be developed for the marketable production of new pigments, using microbial cultures, viz., fungi, and bacteria. To address the issue of the natural coloring agents, this review presents the recent trends in several studies of microbial pigments, their biological properties and industrial applications.

Influence of the Intrinsic Characteristics of Cementitious Materials on Biofouling in the Marine Environment

Coastal marine ecosystems provide essential benefits and services to humanity, but many are rapidly degrading. Human activities are leading to significant land take along coastlines and to major changes in ecosystems. Ecological engineering tools capable of promoting large-scale restoration of coastal ecosystems are needed today in the face of intensifying climatic stress and human activities. Concrete is one of the materials most commonly used in the construction of coastal and marine infrastructure. Immersed in seawater, concretes are rapidly colonized by microorganisms and macroorganisms. Surface colonization and subsequent biofilm and biofouling formation provide numerous advantages to these organisms and support critical ecological and biogeochemical functions in the changing marine environment. The new challenge of the 21st century is to develop innovative concretes that, in addition to their usual properties, provide improved bioreceptivity in order to enhance marine biodiversity. The aim of this study is to master and clarify the intrinsic parameters that influence the bioreceptivity (biocolonization) of cementitious materials in the marine environment. By coupling biofilm (culture-based methods) and biofouling (image-analysis-based method and wet-/dry-weight biomass measurement) quantification techniques, this study showed that the application of a curing compound to the concrete surface reduced the biocolonization of cementitious materials in seawater, whereas green formwork oil had the opposite effect. This study also found that certain surface conditions (faceted and patterned surface, rough surface) promote the bacterial and macroorganism colonization of cementitious materials. Among the parameters examined, surface roughness proved to be the factor that promotes biocolonization most effectively. These results could be taken up in future recommendations to enable engineers to eco-design more eco-friendly marine infrastructure and develop green-engineering projects.

An Overview on Industrial and Medical Applications of Bio-Pigments Synthesized by Marine Bacteria

Marine bacterial species contribute to a significant part of the oceanic population, which substantially produces biologically effectual moieties having various medical and industrial applications. The use of marine-derived bacterial pigments displays a snowballing effect in recent times, being natural, environmentally safe, and health beneficial compounds. Although isolating marine bacteria is a strenuous task, these are still a compelling subject for researchers, due to their promising avenues for numerous applications. Marine-derived bacterial pigments serve as valuable products in the food, pharmaceutical, textile, and cosmetic industries due to their beneficial attributes, including anticancer, antimicrobial, antioxidant, and cytotoxic activities. Biodegradability and higher environmental compatibility further strengthen the use of marine bio-pigments over artificially acquired colored molecules. Besides that, hazardous effects associated with the consumption of synthetic colors further substantiated the use of marine dyes as color additives in industries as well. This review sheds light on marine bacterial sources of pigmented compounds along with their industrial applicability and therapeutic insights based on the data available in the literature. It also encompasses the need for introducing bacterial bio-pigments in global pigment industry, highlighting their future potential, aiming to contribute to the worldwide economy.