Poly(ε-caprolactone) (PCL) is a synthetic plastic known for its excellent physicochemical properties and a wide range of applications in packaging, coatings, foaming, and agriculture. In medicine, its versatility allows it to function as a scaffold for drug delivery, sutures, implants, tissue engineering, and 3D printing. In addition to its biocompatibility, PCL’s most notable characteristic is its biodegradability. However, this property is affected by temperature, microbial activity, and environmental conditions, which means PCL can sometimes remain in nature for long periods. This review shows that various types of microorganisms can efficiently degrade PCL, including different strains of Pseudomonas spp., Streptomyces spp., Alcaligenes faecalis, and fungi like Aspergillus oryzae, Fusarium spp., Rhizopus delemar, and Thermomyces lanuginosus. These microorganisms produce enzymes such as lipases, esterases, and cutinases that break down PCL into smaller molecules that act as substrates. The review also examines the phylogenetic diversity of organisms capable of biodegrading PCL, the biochemical pathways involved in this process, and specific aspects of the genetic framework responsible for the expression of the enzymes that facilitate degradation. Targeted research on microbial PCL biodegradation and its practical applications could significantly aid in reducing and managing plastic waste on a global ecological scale.

The phytohormones cytokinins are essential mediators of developmental and environmental signaling, primarily during cell division and endophytic interactions, among other processes. Considering the limited understanding of the regulatory mechanisms that affect the growth and bioactivity of the medicinal plant Nepeta nuda (Lamiaceae), our study aimed to explore how cytokinins influence the plant's metabolic status. Exogenous administration of active cytokinin forms on in vitro N. nuda internodes stimulated intensive callus formation and de novo shoot regeneration, leading to a marked increase in biomass. This process involved an accumulation of oxidants, which were scavenged by peroxidases using phenolics as substrates. The callus tissue formed upon the addition of the cytokinin 6-benzylaminopurine (BAP) acted as a sink for sugars and phenolics during the allocation of nutrients between the culture medium and regenerated plants. In accordance, the cytokinin significantly enhanced the content of polar metabolites and their respective in vitro biological activities compared to untreated in vitro and wild-grown plants. The BAP-mediated accumulation of major phenolic metabolites, rosmarinic acid (RA) and caffeic acid (CA), corresponded with variations in the expression levels of genes involved in their biosynthesis. In contrast, the accumulation of iridoids and the expression of corresponding biosynthetic genes were not significantly affected. In conclusion, our study elucidated the mechanism of cytokinin action in N. nuda in vitro culture and demonstrated its potential in stimulating the production of bioactive compounds. This knowledge could serve as a basis for further investigations of the environmental impact on plant productivity.

Ludisia discolor is commonly known as a jewel orchid due to its variegated leaves. Easy maintenance of the orchid allows it to be used as a test system for various fertilizers and nutrient sources, including aquaponic water (AW). First, we applied DNA barcoding to assess the taxonomic identity of this terrestrial orchid and to construct phylogenetic trees. Next, the vegetative organs (leaf, stem, and root) were compared in terms of the level of metabolites (reducing sugars, proteins, anthocyanins, plastid pigments, phenolics, and antioxidant activity) and nutrient elements (carbon, nitrogen, sodium, and potassium), which highlighted the leaves as most functionally active organ. Subsequently, AW was used as a natural source of fish-derived nutrients, and the orchid growth was tested in hydroponics, in irrigated soil, and in an aquaponic system. Plant physiological status was evaluated by analyzing leaf anatomy and measuring chlorophyll content and chlorophyll fluorescence parameters. These results provided evidence of the beneficial effects of AW on the jewel orchid, including increased leaf formation, enhanced chlorophyll content and photosystems’ productivity, and stimulated and prolonged flowering. The information acquired in the present study could be used in addressing additional aspects of the growth and development of the jewel orchid, which is also known for its medicinal value.

The interest in microbial pectinases is increasing due to their use in the biotechnological and food industries in response to global demand. In this study, among the 22 halophilic bacterial strains screened, 20 showed pectinase activity. The highest activity was measured for Virgibacillus salarius strain 434. As pectinase production meets many parameter optimization constraints, optimal production conditions for maximizing the yield of the pectinase synthesized using the investigated strain were followed. Enzyme purification was accomplished at up to 11.5-fold via ultrafiltration and gel filtration chromatography, until the enzyme’s specific activity had increased 10-fold (104.3 U/mg). The enzyme’s molecular weight was determined to be 68 kDa. Km and Vmax values of 0.38 mg/mL and 120 U/mg, respectively, were determined. The purified pectinase from Virgibacillus salarius strain 434 showed good thermal stability. A half-life of 20 min at 70 °C and high catalytic activity under haloalkaline conditions (pH 9 and 70 g L⁻¹ NaCl) were observed. Its storage stability at −20 °C exceeded 2 months. This demonstrates its potential for application in industries where these extremes are present, as the harsh conditions in industrial processes require novel pectinases with unique properties instead of the use of hazardous chemicals.

Biodegradation is an advanced method for reducing plastic waste in the environment, involving the participation of microbial communities with plastic-degrading properties. Our study presents a novel halophilic community isolated from the plastic-contaminated region in Burgas Lake, Bulgaria. In a medium containing 15% sodium chloride, the community can degrade a significant amount of polycaprolactone (PCL) as a sole carbon source, as well as the plastics polystyrene (PS) and polypropylene (PP), albeit to a lesser extent. The community showed high hydrophobicity and the ability to form a biofilm on PCL beads, as well as high esterase activity and significant biodegradation capacity, as demonstrated by measuring the weight of the PCL material after cultivation for 4 and 8 weeks. Moreover, a scanning electron microscopy (SEM) analysis revealed visible cracks, craters, and holes in the surface of the polymer particles. The metagenomic study revealed that Halomonas profundus dominated the community with a proportion of 95.13%, followed by Alloalcanivorax venustensis (2.73%), Chromohalobacter marismortui (0.72%), and Halomonas caseinilytica (0.78%). However, most of the species in the community were not previously known as PCL-degrading. Thus, studying the diversity of the halophile community can significantly improve our fundamental understanding and clarify their potential applications for environmental and water–plastic remediation.

Economic development increases and brings about issues such as the secure supply of food in a sustainable way. Phytases are enzymes catalyzing phytate hydrolysis to release phosphorus in an inorganic form. Animal feeds could be supplemented with bacterial phytases to increase their phosphorus and micronutrients bioavailability. To the best of our knowledge, this is the first report on the purification and characterization of an alkalophilic phytase from Cobetia marina. The purified newly isolated phytase from the halophilic Cobetia marina strain 439 appears to be appropriate for use as an additive in food and feed processing. Its molecular weight was determined to be 43 kDa by gel filtration and 40 kDa by SDS–polyacrylamide gel electrophoresis. The purified enzyme had maximum activity at pH 8.0 and 45 °C, while at 70 °C, it was 80% and about 50% at 80 °C for 40 min, showing its thermostability. Enzyme activity was retained at a broad pH range from 6.5 to 9.0. The half-life of the phytase of 15 min at pH 10 and 30 min at pH 4.0 was registered. The enzyme was proven to be with high substrate specificity. In addition, the purified phytase showed strong proteolytic tolerance against trypsin and pepsin. The pH profile, its thermostability, and proteolytic tolerance of the studied phytase as a halophilic bacterial product determine it as a unique candidate for application in agriculture, food, and feed industries.