Search Results (11)

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(3HB-co-3HHx)) is a representative PHA copolymer that can improve the mechanical limitations of polyhydroxybutyrate (P(3HB)). Although genetic engineering can facilitate 3HHx incorporation, it often compromises cell growth and reduces polymer molecular weight owing to metabolic disruptions caused by the deletion of acetoacetyl coenzyme A (acetyl-CoA) reductase (PhaB). To address this issue, native strains capable of producing high levels of 3HHx were identified via oil-based Cupriavidus screening. Eight PHA-producing strains were isolated from various samples and Cupriavidus sp. Oh_1 exhibited the highest polyhydroxybutyrate (PHB) production at 15.23 g/L from 17.2 g/L of biomass using soybean oil. Moreover, Oh_1/phaC_RaJ_Pa, containing enoyl-CoA hydratase (phaJ) and PHA synthetase (phaC), was identified as the most effective novel strain producing the highest 3HHx mole fraction, 48.93 g/L of PHA from 52.3 g/L of biomass and achieving a maximum 3HHx accumulation of 27.2 mol%. The resulting P(3HB-co-3HHx) showed a higher Mw (12.3 × 10⁵) compared with P(3HB-co-3HHx) produced by the phaB-deleted strain (14.6 × 10⁴). Higher production of 3HHx was attributed to the higher expression of phaC_Ra and phaJ_Pa in Oh_1, with log2 fold changes of 2.94 and 8.2, respectively, as well as the upregulation of certain β-oxidation encoding operons. Collectively, these findings highlight a strain capable of synthesizing a substantial 3HHx fraction without requiring gene deletions or extensive genetic modifications. Full article

Ultraviolet (UV)-induced mutagenesis is a cost-effective and straightforward technique for introducing random genetic variations without the use of chemical reagents or genetic engineering. It is commonly employed to enhance enzyme activity in industrial trains. In this study, Trichoderma sp. was exposed to UV radiation at varying distances (4, 9, and 13 cm) and durations (2, 4, 6, and 8 min) to induce mutations. The activities of endoglucanase (EG), β-glucosidase (BGL), and cellobiohydrolase (CBH) were assessed following treatment. The 4 cm exposure distance yielded the highest enhancement, with EG, BGL, and CBH activities increasing 1.5-, 1.3-, and 0.9-fold, respectively. When the distance was fixed at 4 cm, the optimal exposure time was identified as 4 min, yielding further enhancements of 1.9-, 1.6-, and 1.4-fold, respectively. The resulting mutant, designated Mut-4, was scaled up in a 10-L bioreactor to assess its industrial applicability. Mut-4 retained its enhanced performance, achieving 1.9-, 2.0-, and 1.4-fold enhancements in EG, BGL, and CBH activities, respectively, compared with the original strain. These findings indicate that combining UV-induced mutagenesis with basic screening is an effective strategy for enhancing cellulolytic enzyme production, representing a promising approach for lignocellulosic biomass conversion. Full article

This study optimized operating parameters to enhance cellulase production and evaluated scale-up feasibility in submerged fermentation (SmF) using Trichoderma sp. KMF006. Flask-scale experiments assessed the effects of Avicel:cellulose ratios (4:0–0:4), agitation speeds (150–210 rpm), and turbulence (baffled vs. non-baffled flasks), with optimized conditions applied to a 10 L bioreactor. A 3:1 Avicel:cellulose ratio (A3C1) significantly accelerated cellulase production, reaching peak activity 6 days earlier than Avicel alone. An agitation speed of 180 rpm was optimal, balancing enzyme activity and energy efficiency. Turbulence enhanced cellulase yields, with baffled flasks increasing EG, BGL, and CBH activities 19.9-, 6.2-, and 8.9-fold, respectively, compared to the control. Biochar further improved cellulase production but only under turbulent conditions, demonstrating a synergistic effect. At the bioreactor scale, the A3-180_Imp (A3C1, 180 rpm, impeller-induced turbulence) achieved the highest enzymatic activity (33.60 U/mL EG, 3.46 U/mL BGL, and 0.63 U/mL CBH). The filter paper unit (FPU) was 84 FPU/mL, a two-fold increase compared to the control. However, excessive turbulence at 210 rpm reduced enzyme stability, emphasizing the importance of balancing shear stress. These findings provide a systematic framework for optimizing SmF conditions, highlighting the significance of balancing hydrodynamic conditions for efficient cellulase production at an industrial scale. Full article

Soils co-contaminated with petroleum hydrocarbons (PHs) and heavy metals pose significant challenges, such as reduced bioavailability of pollutants, toxic effects on soil microorganisms, and unpredictable chemical interactions. These complex interactions hinder effective remediation. Phytoremediation, which utilizes plant and microbial processes, offers a sustainable and eco-friendly approach. However, its effectiveness is often constrained by the intricate interplay among PHs, heavy metals, and soil components, which complicates pollutant degradation and microbial activity. This review explores the interactions between enhancement strategies, including soil amendments, plant growth-promoting bacteria (PGPB), and genetic engineering, which can synergistically enhance pollutant degradation and remediation efficiency. Key challenges include competition for soil adsorption sites among contaminants, microbial community disruptions, and environmental variability. Moreover, the limitations of these strategies, including their reliance on specific plant species, sensitivity to environmental variability, and the necessity for long-term monitoring, are discussed. The proposed solutions focus on integrating emerging technologies and interdisciplinary approaches to overcome these challenges and improve pollutant removal efficiency. Future advancements in interdisciplinary approaches, integrating biological techniques with technological innovations, are highlighted as key to addressing the complexities of co-contaminated environments and improving pollutant removal efficiency. Full article

This study highlights the differences in the metabolomes of cow milk yoghurt (CY) and goat milk yoghurt (GY) using a nuclear magnetic resonance (NMR)-based metabolomic approach. The 1H HRMAS-NMR spectrum displayed 21 metabolites comprising organic acids, sugars, amino acids, amino acid derivatives and phospholipids. The orthogonal partial least squares discriminant analysis model clearly separated CY and GY groups, implying differences in metabolite composition. The corresponding Variable Importance in Projection (VIP) plot revealed that choline, sn-glycero-3-phosphocholine, O-phosphocholine, fucose, citrate, sucrose, glucose and lactose mainly contributed to the group separation (VIP > 1). Hierarchical cluster analysis further confirmed the metabolome similarities and differences between CY and GY. Additionally, 12 significantly differential metabolites (with a fold change > 1.5 and p-value < 0.05) were identified, with 1 downregulated and 11 upregulated. Pathway impact analysis revealed the correlation of significant metabolites with starch and sucrose metabolism, galactose metabolism, and the citrate cycle. Furthermore, receiver operating characteristic curve analysis identified eight metabolites (choline, sn-glycero-3-phosphocholine, fucose, O-phosphocholine, glucose, citrate, 2-oxoglutarate, lactose and sucrose) as candidate biomarkers. This study represents the first utilization of HRMAS-NMR to analyze the metabolomic profiles of yoghurt made from cow and goat milk. In conclusion, these findings provide preliminary information on how NMR-based metabolomics can discriminate the metabolomes of yoghurt prepared from the milk of two different animals, which may be valuable for authenticity and adulteration assessments. Full article

The whole genome sequence of Lactiplantibacillus plantarum DJF10, isolated from Korean raw milk, is reported, along with its genomic analysis of probiotics and safety features. The genome consists of 29 contigs with a total length of 3,385,113 bp and a GC content of 44.3%. The average nucleotide identity and whole genome phylogenetic analysis showed the strain belongs to Lactiplantibacillus plantarum with 99% identity. Genome annotation using Prokka predicted a total of 3235 genes, including 3168 protein-coding sequences (CDS), 59 tRNAs, 7 rRNAs and 1 tmRNA. The functional annotation results by EggNOG and KEGG showed a high number of genes associated with genetic information and processing, transport and metabolism, suggesting the strain’s ability to adapt to several environments. Various genes conferring probiotic characteristics, including genes related to stress adaptation to the gastrointestinal tract, biosynthesis of vitamins, cell adhesion and production of bacteriocins, were identified. The CAZyme analysis detected 98 genes distributed under five CAZymes classes. In addition, several genes encoding carbohydrate transport and metabolism were identified. The genome also revealed the presence of insertion sequences, genomic islands, phage regions, CRISPR-cas regions, and the absence of virulence and toxin genes. However, the presence of hemolysin and antibiotic-resistance-related genes detected in the KEGG search needs further experimental validation to confirm the safety of the strain. The presence of two bacteriocin clusters, sactipeptide and plantaricin J, as detected by the BAGEL 4 webserver, confer the higher antimicrobial potential of DJF10. Altogether, the analyses in this study performed highlight this strain’s functional characteristics. However, further in vitro and in vivo studies are required on the safety assurance and potential application of L. plantarum DJF10 as a probiotic agent. Full article

Concrete pavement proportions are increasing in Korean expressways, resulting in increased maintenance cost. The length of degenerate concrete pavements that have exceeded the design life (20 years) was 1150 km in 2015 and 2605 km in 2020 and is expected to rapidly increase. To extend the service life of concrete pavements, life-cycle cost (LCC) analysis was conducted on asphalt and concrete overlays, based on the different maintenance methods. LCC analysis was performed when the shoulder was used and when it was not used between 6000 and 35,000 AADT traffic according to the two-lane and four-lane traffic. During overlay, one lane was completely blocked, and the value per vehicle was converted into the user cost using the Construction Analysis for Pavement Rehabilitation Strategies software, according to whether the shoulder was used to maintain the number of lanes. In addition, LCC analysis was conducted by examining the construction cost and life-cycle according to each overlay method. When the shoulder was used, the total construction cost decreased, owing to the reduction in user cost, indicating that the implementation of the traffic measure of using the road shoulder improves user satisfaction and cost. The asphalt overlay was observed to be more favorable than concrete overlay in terms of the initial total construction cost. However, under a 20-year cycle, the economic efficiency of concrete overlay was higher than that of asphalt overlay. After repairing the deteriorated target sections of concrete pavements, the overlay method (asphalt or concrete) ought to be selected according to the target service life for beneficial economic effect. Concrete overlay was to obtain about 20% or greater LCC effect compared to asphalt overlay, and at least 5% or more additional LCC effect obtained when the shoulder was used. Full article

The recent surge in environmental awareness and consumer demand for stable, healthy, and safe foods has led the packaging and food sectors to focus on developing edible packaging materials to reduce waste. Edible films and coatings as a modern sustainable packaging solution offer significant potential to serve as a functional barrier between the food and environment ensuring food safety and quality. Whey protein is one of the most promising edible biopolymers in the food packaging industry that has recently gained much attention for its abundant nature, safety, and biodegradability and as an ecofriendly alternative of synthetic polymers. Whey protein isolate and whey protein concentrate are the two major forms of whey protein involved in the formation of edible films and coatings. An edible whey film is a dry, highly interacting polymer network with a three-dimensional gel-type structure. Films/coatings made from whey proteins are colorless, odorless, flexible, and transparent with outstanding mechanical and barrier properties compared with polysaccharide and other-protein polymers. They have high water vapor permeability, low tensile strength, and excellent oxygen permeability compared with other protein films. Whey protein-based films/coatings have been successfully demonstrated in certain foods as vehicles of active ingredients (antimicrobials, antioxidants, probiotics, etc.), without considerably altering the desired properties of packaging films that adds value for subsequent industrial applications. This review provides an overview of the recent advances on the formation and processing technologies of whey protein-based edible films/coatings, the incorporation of additives/active ingredients for improvement, their technological properties, and potential applications in food packaging. Full article

The odor released from environmental facilities is recognized as a major problem in environmental industries. In this study, reactive absorption, using an electrolyzed water solution (electrolyzed water scrubber, EWS), was developed to treat the odorous gases H₂S and NH₃, which are representative odorous substances. In addition, a numerical model composed of mass transfer coefficients and zero-order kinetic constants was established to predict the performance of EWS. The model was verified through experiments and data fittings. In the experiments, the concentration of H₂S varied from 500 to 2000 ppm, while NH₃ was fixed at 500 ppm. The results revealed that the H₂S removal rate varied depending on the inlet H₂S concentration, but no changes were observed for NH₃. The numerical model appropriately described the experimental results to further predict the performance of EWS. The model prediction results for the shock loading of H₂S indicated that a 100% removal rate can be achieved by increasing the current density to 70 mA cm⁻² or higher. Finally, the EWS can be used to reduce the odor, owing to its flexible operation that responds to fluctuating loading rates. Full article

Geographical origin and authenticity are the two crucial factors that propel overall cheese perception in terms of quality and price; therefore, they are of great importance to consumers and commercial cheese producers. Herein, we demonstrate a rapid, accurate method for discrimination of domestic and import mozzarella cheeses in the Republic of Korea by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The protein profiles’ data aided by multivariate statistical analysis successfully differentiated farmstead and import mozzarella cheeses according to their geographical location of origin. A similar investigation within domestic samples (farmsteads/companies) also showed clear discrimination regarding the producer. Using the biomarker discovery tool, we identified seven distinct proteins, of which two (m/z 7407.8 and 11,416.6) were specific in farmstead cheeses, acting as potential markers to ensure authentication and traceability. The outcome of this study can be a good resource in building a database for Korean domestic cheeses. This study also emphasizes the combined utility of MALDI-TOF MS and multivariate analysis in preventing fraudulent practices, thereby ensuring market protection for Korean farmstead cheeses. Full article

To evaluate the safety and risk assessment of cheese consumption in the Republic of Korea, sixty cheese samples purchased from the farmstead and retails markets (imported) were analyzed for their biogenic amine (BA) contents. The BA profiles and quantities of eight amines (tryptamine, 2-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine, and spermine) were determined using high-performance liquid chromatography (HPLC). Spermine was the only amine detectable in all the samples. The BAs of fresh cheeses from both farmstead and retail markets were mostly undetectable, and comparatively at lower levels (<125 mg/kg) than ripened samples. Putrescine was undetectable in all the domestic ripened cheeses. The sum of BA levels in the imported ripened cheeses of Pecorino Romano (1889.75 mg/kg) and Grana Padano (1237.80 mg/kg) exceeds >1000 mg/kg, of which histamine accounts nearly 86 and 77% of the total levels, respectively. The tolerable limits of the potential toxic amines, histamine and tyramine surpassed in four and three imported ripened samples, respectively. Furthermore, the presence of potentiators (putrescine and cadaverine) together in samples even with a lower level of toxic amines alarms the risk in consumption. Therefore, adoption of strict hygienic practices during the entire chain of cheese production, along with obligatory monitoring and regulation of BA in cheeses seems to be mandatory to ensure the safety of the consumers. Full article