Natural Secondary Metabolites Research Articles

Versatile filamentous fungal host highly-producing heterologous natural products developed by genome editing-mediated engineering of multiple metabolic pathways

Natural secondary metabolites are medically, agriculturally, and industrially beneficial to humans. For mass production, a heterologous production system is required, and various metabolic engineering trials have been reported in Escherichia coli and Saccharomyces cerevisiae to increase their production levels. Recently, filamentous fungi, especially Aspergillus oryzae, have been expected to be excellent hosts for the heterologous production of natural products; however, large-scale metabolic engineering has hardly been reported. Here, we elucidated candidate metabolic pathways to be modified for increased model terpene production by RNA-seq and metabolome analyses in A. oryzae and selected pathways such as ethanol fermentation, cytosolic acetyl-CoA production from citrate, and the mevalonate pathway. We performed metabolic modifications targeting these pathways using CRISPR/Cas9 genome editing and demonstrated their effectiveness in heterologous terpene production. Finally, a strain containing 13 metabolic modifications was generated, which showed enhanced heterologous production of pleuromutilin (8.5-fold), aphidicolin (65.6-fold), and ophiobolin C (28.5-fold) compared to the unmodified A. oryzae strain. Therefore, the strain generated by engineering multiple metabolic pathways can be employed as a versatile highly-producing host for a wide variety of terpenes.

Formononetin Mitigates Liver Fibrosis via Promoting Hepatic Stellate Cell Senescence and Inhibiting EZH2/YAP Axis.

Formononetin (FMN), an isoflavone mainly derived from leguminous plants, is a natural secondary metabolite with valuable pharmacological effects in the regulation of numerous chronic diseases. This study aimed to investigate the influence of FMN on liver fibrosis and clarify the underlying mechanisms. In vivo FMN administration protected mice from BDL or CCl4-induced liver fibrosis. In vitro experimental findings revealed the FMN-mediated inhibitory effects on hepatic stellate cell (HSC) activation. Transcriptome analyses showed that YAP silencing and the subsequent HSC senescence might be responsible for the FMN-mediated antifibrotic outcomes. Furthermore, FMN suppressed EZH2 and its substrate H3K27me3, which are essential for YAP activation and HSC senescence. Remarkably, EZH2 overexpression reversed the FMN potential therapeutic effects on YAP that impact HSC senescence. Our study demonstrated that FMN potentially mitigated hepatic fibrosis by inhibiting EZH2/YAP axis and promoting HSC senescence. Together, these findings provide insights into the prospective therapeutic targets of FMN in liver fibrosis management.

The Role of Plant Extracts in Enhancing Nutrition and Health for Dogs and Cats: Safety, Benefits, and Applications.

Plant extracts, derived from various natural sources, encompass primary and secondary metabolites, which include plant polysaccharides, polyphenols, alkaloids, flavonoids, glycosides, terpenes, and volatile oils. These compounds exhibit a range of biological activities such as antioxidant, anti-inflammatory, and antimicrobial functions. Currently, polyphenols and other bioactive compounds are being incorporated into the diets of farm animals, fish, and pets to promote health benefits. Despite this, the application and potential of plant extracts in canine and feline nutrition have not been comprehensively explored. Many aspects of the mechanisms underlying the action of these plant metabolites remain to be analyzed and elucidated. Furthermore, leveraging natural plant extracts for the treatment of clinical conditions in dogs and cats is a crucial component of clinical nutrition. Consequently, this review aims to highlight the impact of plant extracts on overall health, gastrointestinal health, immune health, cardiovascular health, redox balance, and pathology in dogs and cats.

Evaluation of the antimicrobial properties of natural extracts of Ganoderma lucidum

There is a growing importance of alternative anticancer and anti-inflammatory treatments. Current interest lies in natural medicine and secondary metabolites present in plants, particularly focusing on triterpenes. Ganoderma lucidum is a fungal species of significant commercial interest due to its therapeutic and medicinal properties resulting from secondary metabolites such as polysaccharides and triterpenes. These compounds exhibit antitumor activity and bolster the immune system. The study aimed to assess the antimicrobial activity of G. lucidumextracts, both commercial and wild. The content of ganoderic acids in all extracts showed a slight difference in concentration between commercial and wild extracts. However, no bacterial inhibition halos were observed in any of the strains used. The presence of varying concentrations of ganoderic acids among treatments underscores the importance of optimizing and standardizing a comprehensive strategy for extracting secondary metabolites, focusing on producing high-quality supplements and pharmaceutical products. Furthermore, preserving the stability of the obtained triterpenes is necessary due to their importance in the medicinal properties of the fungus.

Gallic acid synergistically enhances the antibacterial activity of azithromycin in MRSA.

The rise of antibiotic resistance in existing pathogens has been identified as a major threat to global healthcare in the twenty-first century. This resistance has consequences such as increased cost and prolonged hospital stays, treatment failure, and ultimately increased risk of patient mortality. It is therefore imperative to develop strategies to combat drug resistance. Combined treatment of common antibiotics and natural compounds is one of the most effective methods against resistant bacterial infections. Gallic acid (GA) is a natural secondary metabolite abundantly found in plants and has significant medicinal effects in various aspects of health. In this research, the antibacterial effects of azithromycin (AZM) and GA alone and in combination with each other were investigated on planktonic and biofilm forms of methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), and Pseudomonas aeruginosa (P. aeruginosa). The results showed that the combination of AZM/GA had an additive effect against MSSA and P. aeruginosa and a synergistic effect against MRSA. In addition, combining these two agents significantly reduced the minimum biofilm inhibitory concentration (MBIC) of AZM and GA in the MRSA strain. Finally, the level of ROS generation in the effect of AZM plus GA was evaluated in the bacteria. Among the studied strains, ROS production was significantly increased in combination treatment compared to AZM alone in MRSA. The results show that the combination of AZM and GA has a significant effect against MRSA and can be considered as an effective treatment option.

Plant-Derived Terpenoids: A Plethora of Bioactive Compounds with Several Health Functions and Industrial Applications-A Comprehensive Overview.

Terpenoids are a large class of natural secondary plant metabolites which are highly diverse in structure, formed from isoprene units (C-5), associated with a wide range of biological properties, including antioxidant, antimicrobial, anti-inflammatory, antiallergic, anticancer, antimetastatic, antiangiogenesis, and apoptosis induction, and are considered for potential application in the food, cosmetics, pharmaceutical, and medical industries. In plants, terpenoids exert a variety of basic functions in growth and development. This review gives an overview, highlighting the current knowledge of terpenoids and recent advances in our understanding of the organization, regulation, and diversification of core and specialized terpenoid metabolic pathways and addressing the most important functions of volatile and non-volatile specialized terpenoid metabolites in plants. A comprehensive description of different aspects of plant-derived terpenoids as a sustainable source of bioactive compounds, their biosynthetic pathway, the several biological properties attributed to these secondary metabolites associated with health-promoting effects, and their potential industrial applications in several fields will be provided, and emerging and green extraction methods will also be discussed. In addition, future research perspectives within this framework will be highlighted. Literature selection was carried out using the National Library of Medicine, PubMed, and international reference data for the period from 2010 to 2024 using the keyword "terpenoids". A total of 177,633 published papers were found, of which 196 original and review papers were included in this review according to the criteria of their scientific reliability, their completeness, and their relevance to the theme considered.

ANTIMICROBIAL WOUND DRESSINGS FOR FULL-THICKNESS INFECTED BURN WOUNDS.

Infection of wounds delays healing, increases treatment costs, and leads to major complications. Current methods to manage such infections include antibiotic ointments and antimicrobial wound dressings, both of which have significant drawbacks, including frequent reapplication and contribution to antimicrobial resistance. In this work, we developed wound dressings fabricated with a medical-grade polyurethane coating composed of natural plant secondary metabolites, cinnamaldehyde, and alpha-terpineol. Our wound dressings are easy to change and do not adhere to the wound bed. They kill gram-positive and -negative microbes in infected wounds due to the Food and Drug Administration-approved for human consumption components. The wound dressings were fabricated by dip coating. Antimicrobial efficacy was determined by quantifying the bacteria colonies after a 24 h of immersion. Wound healing and bacterial reduction were assessed in an in vivo full-thickness porcine burn model. Our antimicrobial wound dressings showed a > 5-log reduction (99.999%) of different gram-positive and gram-negative bacteria, while maintaining absorbency. In the in vivo porcine burn model, our wound dressings were superior to bacitracin in decreasing bacterial burden during daily changes, without interfering with wound healing. Additionally, the dressings had a significantly lower adhesion to the wound bed. Our antimicrobial wound dressings reduced the burden of clinically relevant bacteria more than commercial antimicrobial wound dressings. In an in vivo infected burn wound model, our coatings performed as well or better than bacitracin. We anticipate that our wound dressings would be useful for the treatment of various types of acute and chronic wounds.

Structure based screening and molecular docking with dynamic simulation of natural secondary metabolites to target RNA-dependent RNA polymerase of five different retroviruses.

Viral diseases pose a serious global health threat due to their rapid transmission and widespread impact. The RNA-dependent RNA polymerase (RdRp) participates in the synthesis, transcription, and replication of viral RNA in host. The current study investigates the antiviral potential of secondary metabolites particularly those derived from bacteria, fungi, and plants to develop novel medicines. Using a virtual screening approach that combines molecular docking and molecular dynamics (MD) simulations, we aimed to discover compounds with strong interactions with RdRp of five different retroviruses. The top five compounds were selected for each viral RdRp based on their docking scores, binding patterns, molecular interactions, and drug-likeness properties. The molecular docking study uncovered several metabolites with antiviral activity against RdRp. For instance, cytochalasin Z8 had the lowest docking score of -8.9 (kcal/mol) against RdRp of SARS-CoV-2, aspulvinone D (-9.2 kcal/mol) against HIV-1, talaromyolide D (-9.9 kcal/mol) for hepatitis C, aspulvinone D (-9.9 kcal/mol) against Ebola and talaromyolide D also maintained the lowest docking score of -9.2 kcal/mol against RdRp enzyme of dengue virus. These compounds showed remarkable antiviral potential comparable to standard drug (remdesivir -7.4 kcal/mol) approved to target RdRp and possess no significant toxicity. The molecular dynamics simulation confirmed that the best selected ligands were firmly bound to their respective target proteins for a simulation time of 200 ns. The identified lead compounds possess distinctive pharmacological characteristics, making them potential candidates for repurposing as antiviral drugs against SARS-CoV-2. Further experimental evaluation and investigation are recommended to ascertain their efficacy and potential.

Genomic insights into the evolution of secondary metabolism of Escovopsis and its allies, specialized fungal symbionts of fungus-farming ants.

The metabolic intimacy of symbiosis often demands the work of specialists. Natural products and defensive secondary metabolites can drive specificity by ensuring infection and propagation across host generations. But in contrast to bacteria, little is known about the diversity and distribution of natural product biosynthetic pathways among fungi and how they evolve to facilitate symbiosis and adaptation to their host environment. In this study, we define the secondary metabolism of Escovopsis and closely related genera, symbionts in the gardens of fungus-farming ants. We ask how the gain and loss of various biosynthetic pathways correspond to divergent lifestyles. Long-read sequencing allowed us to define the chromosomal features of representative Escovopsis strains, revealing highly reduced genomes composed of seven to eight chromosomes. The genomes are highly syntenic with macrosynteny decreasing with increasing phylogenetic distance, while maintaining a high degree of mesosynteny. An ancestral state reconstruction analysis of biosynthetic pathways revealed that, while many secondary metabolites are shared with non-ant-associated Sordariomycetes, 56 pathways are unique to the symbiotic genera. Reflecting adaptation to diverging ant agricultural systems, we observe that the stepwise acquisition of these pathways mirrors the ecological radiations of attine ants and the dynamic recruitment and replacement of their fungal cultivars. As different clades encode characteristic combinations of biosynthetic gene clusters, these delineating profiles provide important insights into the possible mechanisms underlying specificity between these symbionts and their fungal hosts. Collectively, our findings shed light on the evolutionary dynamic nature of secondary metabolism in Escovopsis and its allies, reflecting adaptation of the symbionts to an ancient agricultural system.IMPORTANCEMicrobial symbionts interact with their hosts and competitors through a remarkable array of secondary metabolites and natural products. Here, we highlight the highly streamlined genomic features of attine-associated fungal symbionts. The genomes of Escovopsis species, as well as species from other symbiont genera, many of which are common with the gardens of fungus-growing ants, are defined by seven chromosomes. Despite a high degree of metabolic conservation, we observe some variation in the symbionts' potential to produce secondary metabolites. As the phylogenetic distribution of the encoding biosynthetic gene clusters coincides with attine transitions in agricultural systems, we highlight the likely role of these metabolites in mediating adaptation by a group of highly specialized symbionts.

Polyphenol-Rich Extracts from Agroindustrial Waste and Byproducts: Results and Perspectives According to the Green Chemistry and Circular Economy.

Polyphenols are natural secondary metabolites found in plants endowed with multiple biological activities (antioxidant, anti-inflammatory, antimicrobial, cardioprotective, and anticancer). In view of these properties, they find many applications and are used as active ingredients in nutraceutical, food, pharmaceutical, and cosmetic formulations. In accordance with green chemistry and circular economy strategies, they can also be recovered from agroindustrial waste and reused in various sectors, promoting sustainable processes. This review described structural characteristics, methods for extraction, biological properties, and applications of polyphenolic extracts obtained from two selected plant materials of the Mediterranean area as olive (Olea europaea L.) and pomegranate (Punica granatum L.) based on recent literature, highlighting future research perspectives.

Role of natural secondary metabolites as HIF-1 inhibitors in cancer therapy

Role of natural secondary metabolites as HIF-1 inhibitors in cancer therapy

Antimicrobial Potential of Natural Compounds of Zingiberaceae Plants and their Synthetic Analogues: A Scoping Review of In vitro and In silico Approaches.

There has been increased scientific interest in bioactive compounds and their synthetic derivatives to promote the development of antimicrobial agents that could be used sustainably and overcome antibiotic resistance. We conducted this scoping review to collect evidence related to the antimicrobial potential of diverse natural compounds from Zingiberaceae plants and their synthetic derivatives. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Extension for Scoping Reviews guidelines. The literature search was conducted using PubMed, Web of Science and Scopus electronic databases for relevant studies published from 2012 to 2023. A total of 28 scientific studies fulfilled the inclusion criteria. The authors of these studies implemented in vitro and in silico methods to examine the antimicrobial potency and underlying mechanisms of the investigated compounds. The evidence elucidates the antimicrobial activity of natural secondary metabolites from Zingiberaceae species and their synthetic derivatives against a broad panel of gram-positive and gram-negative bacteria, fungi and viruses. To date, researchers have proposed the application of bioactive compounds derived from Zingiberaceae plants and their synthetic analogues as antimicrobial agents. Nevertheless, more investigations are required to ascertain their efficacy and to broaden their commercial applicability.

The use of botanicals as pesticides: History, development and emerging challenges

The unrestrained use of artificial pesticides over the years has strictly affected the function and dynamics of the ecosystem. The plants are a valuable store providing natural secondary metabolites that can be used as alternative pesticides that are non- pollutive, inexhaustible, everlasting, locally available, simply accessible, environment-friendly and comparatively profitable. It is against this background that scientists have made relentlessly effort to come up with botanicals that can be used as pesticides. The use of botanicals as pesticides has witnessed a rapid expansion in recent years. Plant extracts like nicotine were some of the earliest agricultural botanicals used as early as 17th century. An increasing number of experiments on bio-pesticides occurred in the rapid institutional growth of agricultural research of the early 20th century. Revival in academic and industrial research with a view to developing bio-pesticides transpired in response to increasing costs related with the overexploitation of artificial chemicals. The emergence of novel bio-pesticides has persistently increased since the mid-1990s. Nowadays more and better botanicals are used as pesticides. However, bio-pesticides or botanicals have their limitations some of which include its slower rate of kill in comparison to orthodox chemical pesticides, shorter persistence in the environment and susceptibility to unfavourable environmental conditions. For effective use of bio-pesticides there is need for knowledge-intensive management systems. Plant protection biologists have a sole duty to facilitate an understanding of bio-pesticide efficacy and as well ensure that innovation and knowledge are properly disseminated towards the progress and implementation of sustainable approaches.

Anticancer potential of grifolin in lung cancer treatment through PI3K/AKT pathway inhibition

ObjectiveGrifolin is a natural secondary metabolite isolated from edible fruiting bodies of the mushroom Albatrellus confluens. Grifolin has antitumor activities in several types of cancer. We aimed to determine the effects of grifolin on lung cancer. MethodsWe determined the proliferation, migration, invasion, and apoptosis of lung cancer cells using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, Ethynyl deoxyuridine, colony formation, wound scratch, transwell, flow cytometry, and xenograft mouse assays. Molecular docking evaluated the binding relation between grifolin and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA). The levels of PIK3CA, AKT, and p-AKT were measured by western blot. ResultsGrifolin (10, 20, or 40 μM) inhibited the proliferation, migration, and invasion of lung cancer cells, and induced cell cycle arrest and apoptosis. Grifolin also decreased CDK4, CDK6, and CyclinD1 expression and significantly decreased PIK3CA and p-AKT expression in lung cancer cells. These anticancer effects were abolished by 740Y-P. ConclusionsGrifolin regulates the PI3K/AKT pathway, thus inhibiting lung cancer progression.

Caged xanthone derivatives to promote mitochondria-mediated apoptosis in breast cancer cells

Caged xanthones represent a class of natural secondary metabolites exhibiting significant potential as antitumor agents. These compounds are characterized by their distinct cage-like structures, which offer novel and compelling frameworks for drug design. Nonetheless, there exists a dearth of research focused on the structural modification of these compounds, particularly in relation to their cage-like architectures. This study aims to address this gap by introducing an innovative synthetic method for constructing a novel caged structure that incorporates a widely employed maleimide group. Drawing upon the well-established synthetic approach for dihydroxanthones previously developed within our research group, we successfully synthesized 13 new caged xanthones using the Diels-Alder reaction. Subsequently, we evaluated their anti-proliferative activity against HepG2, A549, and MDA-MB-231 cell lines. The results revealed that compound 10i exhibited IC50 values of 15.86 µM ± 1.29, 19.27 µM ± 1.58, and 12.96 µM ± 0.09 against these cell lines, respectively. Further investigations into the mechanism of action of 10i demonstrated its ability to induce G2/M cell cycle arrest and initiate mitochondria-mediated apoptosis in breast cancer cells.

Feedback regulation of the isoprenoid pathway by SsdTPS overexpression has the potential to enhance plant tolerance to drought stress.

In order to maintain the dynamic physiological balance, plants are compelled to adjust their energy metabolism and signal transduction to cope with the abiotic stresses caused by complex and changeable environments. The diterpenoid natural compound and secondary metabolites, sclareol, derived from Salvia sclarea, has gained significant attention owing to its economic value as a spice material and diverse physiological activities. Here, we focused on the roles and regulatory mechanisms of the sclareol diterpene synthase gene SsdTPS in the resistance of S. sclarea to abiotic stresses. Our results suggested that abiotic stresses could induce the response and upregulation of SsdTPS expression and isoprenoid pathway in S. sclarea. Ectopic expression of SsdTPS conferred drought tolerance in transgenic Arabidopsis, compared with wild-type. Overexpression of SsdTPS enhanced the transcription of ABA signal transduction synthetic regulators and induced the positive feedback upregulating key regulatory genes in the MEP pathway, thereby promoting the increase of ABA content and improving drought tolerance in transgenic plants. In addition, SsdTPS-overexpressed transgenic Arabidopsis improved the responses of stomatal regulatory genes and ROS scavenging enzyme activities and gene expression to drought stress. This promoted the stomatal closure and ROS reduction, thus enhancing water retention capacity and reducing oxidative stress damage. These findings unveil the potentially positive role of SsdTPS in orchestrating multiple regulatory mechanisms and maintaining homeostasis for improved abiotic stress resistance in S. sclarea, providing a novel insight into strategies for promoting drought resistance and cultivating highly tolerant plants.

Liposomal Formulation Improves the Bioactivity of Usnic Acid in RAW 264.7 Macrophage Cells Reducing its Toxicity.

Reactive oxygen species (ROS) production and oxidative stress may be responsible for the onset of several chronic diseases. Usnic acid (UA) is a natural secondary metabolite of lichens with several healthful bioactivities, including antioxidant properties. However, UA is a hydrophobic compound known for its hepatic toxicity. These aspects limit its therapeutic applications. To overcome these drawbacks and improve the pharmacological use of hydrophobic compounds, nanotechnology is widely used. Therefore, the incorporation of UA into appropriate nanocarriers could enhance the bioactivity of UA by increasing its solubility. The aim of this work was to improve the solubility of UA and its bioactivity in the absence of cytotoxicity. In this study, UA loaded liposomes (UA-LP) were developed. The formulations were chemically and physically characterized, and an in vitro release study was performed. Free UA and UA-LP were tested on RAW 264.7 murine macrophages in terms of cytotoxicity, intracellular ROS production, and NO release in the absence or presence of pro-oxidant LPS stimulus. UA-LP showed excellent physical and chemical stability during storage and improved solubility of UA. UA-LP showed an antioxidant effect in the absence of cytotoxicity compared with free UA on LPS-exposed macrophages. For the first time, liposomal formulation improved the beneficial action of UA in terms of solubility and antioxidant activity.

Pharmacognostic studies and thin layer chromatography profile of the aerial parts of Vernonia cinerealess. (Asteraceae)

Vernonia cinerea(VC) Less is synonymously known as Cyanthillium cinereum and Vernonia abbreviate belongs to Asteraceae family. Different parts of the plant are extensively used in traditional medicine for treatment of various disease conditions. However, there was no scientific evaluation of the plant’s pharmacognosy and thin layer chromatography (TLC), which necessitate these studies, to bring out characters that will facilitate its proper identification, standardization and, nature of secondary metabolites in aerial parts of the plant. To carry out detailed pharmacognostic studies and TLC evaluation on the aerial parts of Vernonia cinerea. Aerial plant parts of V. cinerea were studied for their organoleptic, macroscopic, microscopic, physicochemical features and bitterness properties, their elemental and nutritional values were evaluated using standard procedures. In the TLC, reagents were used to evaluate presence of various bioactive constituents in the parts studied. Pharmacognostic studies of aerial parts of VC highlighted features that are diagnostic from microscopic characters and their dimensions, different ergastic substances in the chemomicrocopical study. The elemental analysis showed the presence of macro, micro and trace elements. Nutritionally, there are presence of macro molecules such as carbohydrates, protein and fats. All these will serve as criteria to differentiate it from other species in the same and other families. The TLC profile showed spots of different colour shades after spraying with general and specific reagents and, their Rf values determined. Detailed pharmacognostic studies on the aerial parts of VC showed characters which might be useful to provide information with regard to its identification, standardization and types of phytochemicals present.

Streptomyces Diversity Maps Reveal Distinct High-Specificity Biogeographical and Environmental Patterns Compared to the Overall Bacterial Diversity.

Despite their enormous impact on the environment and humans, the distribution and variety of the biggest natural secondary metabolite producers, the genus Streptomyces, have not been adequately investigated. We developed representative maps from public EMP 16S rRNA amplicon sequences microbiomics data. Streptomyces ASVs were extracted from the EMP overall bacterial community, demonstrating Streptomyces diversity and identifying crucial diversity patterns. Our findings revealed that while the EMP primarily distinguished bacterial communities as host-associated or free-living (EMPO level 1), the Streptomyces community showed no significant difference but exhibited distinctions between categories in EMPO level 2 (animal, plant, non-saline, and saline). Multiple linear regression analysis demonstrated that pH, temperature, and salinity significantly predicted Streptomyces richness, with richness decreasing as these factors increased. However, latitude and longitude do not predict Streptomyces richness. Our Streptomyces maps revealed that additional samplings in Africa and Southeast Asia are needed. Additionally, our findings indicated that a greater number of samples did not always result in greater Streptomyces richness; future surveys may not necessitate extensive sampling from a single location. Broader sampling, rather than local/regional sampling, may be more critical in answering microbial biogeograph questions. Lastly, using 16S rRNA gene sequencing data has some limitations, which should be interpreted cautiously.

Biotechnological production of ectoine: current status and prospects.

Ectoine is an important natural secondary metabolite in halophilic microorganisms. It protects cells against environmental stressors, such as salinity, freezing, drying, and high temperatures. Ectoine is widely used in medical, cosmetic, and other industries. Due to the commercial market demand of ectoine, halophilic microorganisms are the primary method for producing ectoine, which is produced using the industrial fermentation process "bacterial milking." The method has some limitations, such as the high salt concentration fermentation, which is highly corrosive to the equipment, and this also increases the difficulty of downstream purification and causes high production costs. The ectoine synthesis gene cluster has been successfully heterologously expressed in industrial microorganisms, and the yield of ectoine was significantly increased and the cost was reduced. This review aims to summarize and update microbial production of ectoine using different microorganisms, environments, and metabolic engineering and fermentation strategies and provides important reference for the development and application of ectoine.