Search Results (324)

This study developed a two-step statistically integrated optimization framework to identify the effects of key fermentation medium components controlling hyaluronic acid (HA) biosynthesis by Streptococcus zooepidemicus. As an initial phase, the Plackett–Burman design was employed to identify the most influential components among yeast extract, casein, peptone, beef extract, MgSO₄·7H₂O, K₂HPO₄, KH₂PO₄, and (NH₄)₂SO₄ by conducting 12 fermentation runs, and 30 g/L of glucose was used as the carbon source. Among the eight ingredients, yeast extract, MgSO₄·7H₂O, and KH₂PO₄ were identified as the most significant factors in enhancing HA production. The following steps were based on the selection of the best carbon and yeast extract sources. Sucrose was selected as the optimal carbon source among glucose and lactose, and Tastone 900-Baker’s yeast extract was selected as the optimal nitrogen source among various yeast extract sources. The final phase of the optimization procedure employed the Box–Behnken design to determine the optimal concentrations of three ingredients: yeast extract (10–30 g/L), MgSO₄·7H₂O (0.2–2.0 g/L), and KH₂PO₄ (1–4 g/L). The results depicted that the optimized media formulation, composed of 30.0 g/L of yeast extract, 1.16 g/L of MgSO₄·7H₂O, and 4.0 g/L of KH₂PO₄, enhanced HA production and biomass OD600 to 545.9 mg/L with 1250–1500 kDa and 2.53 OD600 in a 250 mL shake flask scale, which was around a 10-fold increase in HA production compared with run #10 of Plackett–Burman (57.42 mg/L). This study provided preliminary results for future process conditions optimization, scale-up studies, and techno-economic evaluation. Full article

In the present study, medium composition of Cordyceps farinosa Cf-GZU06 mycelial fermentation was optimized using response surface methodology. Both intracellular polysaccharides (IPS) and extracellular polysaccharides (EPS) from C. farinosa Cf-GZU06 were obtained and investigated for their structural properties and prebiotic potential. The final medium consisted of 76.170 g/L glucose, 11.056 g/L peptone, 22.201 g/L yeast extract, 0.600 g/L MgSO₄·7H₂O and 1.400 g/L KH₂PO₄ with the maximum mycelial biomass reaching 44.797 g/L. Structural characteristics showed that EPS and IPS had similar primary structures but different fine structures, especially the aggregate states and microstructures. The primary structures of these two polysaccharides showed limited susceptibility in in vitro digestion with no major changes in their molecular weight (MW) profiles, while the fine structure could be altered during digestion process with less than 17% (w/w) reducing sugar detected. Both EPS and IPS could reshape the fecal microbial composition toward a susceptible balance. The production of short-chain fatty acids (SCFAs) including acetate, propionic and butyric acid was significantly increased, and the total SCFAs was increased to 315.18 mM and 302.81 mM by EPS and IPS respectively compared to inulin (279.06 mM). Microbial metabolic profiles showed that EPS and IPS had totally different impacts on bacterial metabolism. These results suggested that EPS and IPS exhibited a potential prebiotic effect under in vitro conditions, supporting their further evaluation as prebiotic candidates. Full article

Twelve white-rot fungal isolates were evaluated for their potential to produce mycelium leather from rice straw, based on growth characteristics, biomass production, and mechanical properties. Among these, Trametes sp. SW25-2 exhibited rapid growth on culture medium and dense mycelial formation on rice straw substrate. The effects of nutrient supplementation, substrate-to-medium ratio, and processing conditions on mycelium-leather formation were systematically examined. No significant differences were observed among different carbon (glucose, maltose, and sucrose) and nitrogen sources (yeast extract, peptone, and ammonium sulphate), indicating that the fungus effectively utilised rice straw as the primary substrate. An optimal ratio of 1 g rice straw to 10 mL culture medium (90.9% moisture content) enabled complete colonisation and the formation of a compact mycelial structure, achieving a maximum tensile strength of 2.78 MPa under optimised hot-pressing conditions (120 °C, 60 s, 1 MPa). Hot-pressing conditions significantly influenced material properties. A higher temperature (120 °C) increased tensile strength but reduced elongation at break, while a lower temperature (60 °C) produced more flexible materials. Scanning electron microscopy revealed that post-treatment and hot pressing transformed the mycelial network into a dense and cohesive structure. The resulting mycelium leather demonstrated suitable physical properties and was successfully fabricated into prototype products, highlighting its potential as a sustainable bio-based material derived from agricultural waste. Full article

Root rot is a major disease restricting the cultivation and production of Polygonatum kingianum Coll. et Hemsl. This study aimed to identify the causal agent and characterize its biological properties. Pathogens were isolated from diseased rhizomes showing typical symptoms, and their pathogenicity was confirmed through Koch’s postulates using both detached rhizome inoculation and field pot experiments with spore suspension irrigation, in which typical root rot symptoms were reproduced. Based on morphological characteristics and multi-locus phylogenetic analysis (ITS, CaM, RPB2, and TUB), the pathogen was identified as Penicillium crustosum. Biological characterization revealed that the optimal conditions for mycelial growth and sporulation were 25 °C and pH 8–9, with Czapek agar being the most suitable medium. Light conditions significantly influenced fungal development; continuous darkness (24 h) favored mycelial growth, while an alternating light/dark cycle (12 h/12 h) significantly enhanced sporulation. Furthermore, the pathogen exhibited the highest utilization efficiency for soluble starch as a carbon source and peptone or yeast extract as a nitrogen source. These physiological traits suggest a strong adaptive capacity of the pathogen to environmental conditions associated with host rhizomes, which may contribute to disease development under cultivation conditions. To our knowledge, this is the first report of P. crustosum causing root rot in P. kingianum. The findings provide a basis for accurate pathogen identification and improve current understanding of the biological characteristics of this pathogen, thereby supporting future studies on disease monitoring and management. Full article

Peach bacterial shot hole is a major disease limiting the yield and quality in most peach-producing areas worldwide. To clarify its etiology and support the development of targeted management strategies, diseased samples were collected from Changli County peach orchards. The pathogen was isolated, purified and verified by Koch’s postulates. Based on morphological, biochemical and multi-locus phylogenetic analyses, the causal agent was identified as Xanthomonas arboricola pv. pruni (isolate TCK-5). Biological characterization revealed that TCK-5 grew optimally in KB and NB medium at 28 °C, pH 7.0–7.5 and 0.5–1.0% NaCl, efficiently utilized glycerol and organic nitrogen source (proteose peptone, beef extract and yeast extract), with light showing no significant effect on growth. The strain TCK-5 exhibited a lethal temperature of 51 °C, indicating that heat treatment above this threshold effectively disinfects pruning tools and contaminated plant debris. Among 18 bactericides tested in vitro, biological bactericide outperformed chemical ones, with 0.3% Tetramycin AS (EC₅₀ = 0.1051 mg/L) and 3% Zhongshengmycin SL (EC₅₀ = 2.9252 mg/L) exhibiting the strongest inhibitory activity. This study fills a regional knowledge gap in the epidemiological distribution of the pathogen in northern China and advances current understanding of X. arboricola pv. pruni occurrence, providing a scientific basis for subsequent epidemic monitoring and integrated control of peach bacterial shot hole. Full article

Optimization of nutrient medium composition and cultivation conditions is a simple tool for directing enzyme biosynthesis of microbial strain towards the synthesis of a desired enzyme with maximum activity. The aim of the present study is to optimize the composition of the nutrient medium and the cultivation conditions for maximum phytase biosynthesis by Aspergillus tubingensis. The most suitable sources of carbon, inorganic and organic nitrogen, phosphorus and salts for obtaining maximum phytase activity were determined. The effect of concentration of medium components on phytase biosynthesis was investigated. The optimal component composition of the nutrient medium was determined to be rice starch, peptone and ammonium oxalate. A response surface methodology was applied for determination of the optimal concentrations of the components of the nutrient medium for maximum phytase biosynthesis. The optimal composition of the nutrient medium was determined to be rice starch 13.5 g/L, peptone 4.84 g/L and ammonium oxalate 2.92 g/L. With the optimized nutrient medium experimental value of 26.68 U/mL, phytase activity was obtained. This value was 185% higher in comparison to the activity obtained with the initial nutrient medium (9.35 U/mL). By a simple optimization of the nutrient medium, a significant increase in phytase activity was achieved. Full article

Rambutan peel, an abundant agro-industrial by-product, is a rich source of ellagitannins (ETs) and represents a promising substrate for the sustainable production of ellagic acid (EA) through solid-state fermentation (SSF). This study aimed to optimize EA release from rambutan peel ETs by SSF using Saccharomyces cerevisiae 227 in column reactors. We applied a central composite design (CCD) to evaluate and optimize the effects of temperature, NaCl concentration, and peptone supplementation on EA production. We also used HPLC/ESI/MS to identify and quantify EA. Maximum EA yields were obtained under central experimental conditions (treatments 15 and 16: 35 °C, 0.53 g/L NaCl, and 8 g/L peptone), reaching 8.36 ± 1.58 and 8.23 ± 0.52 mg/g, respectively. The predictive model estimated a maximum EA production of 8.29 mg/g, experimentally validated, at 34.6 °C, 0.58 g/L NaCl, and 8.26 g/L peptone, yielding 8.27 ± 0.47 mg/g. HPLC/ESI/MS analysis further confirmed EA formation and the presence of biodegradation products derived from geraniin and corilagin, indicating effective ET biotransformation. These findings establish optimized conditions for EA production from rambutan peel ETs via SSF and demonstrate the feasibility of implementing a sustainable bioprocess for the valorization of this agro-industrial residue. Full article

Xylitol is a five-carbon sugar alcohol of industrial interest due to its applications as a food sweetener and sugar substitute. In this study, artificial neural networks combined with a genetic algorithm were evaluated as a data-driven approach for modeling and exploring xylitol production by Spathaspora boniae and Spathaspora brasiliensis during fermentation of sugarcane bagasse hemicellulosic hydrolysate. The dataset comprised 20 experimental points obtained from a face-centered central composite design, using urea, yeast extract, peptone, and ammonium sulfate as input variables. The neural network models showed high goodness-of-fit, with R² values of 0.9952 for S. boniae and 0.9930 for S. brasiliensis. Experimental validation of the optimized conditions resulted in xylitol production of 11.54 ± 0.52 g L⁻¹ for S. boniae and 9.29 ± 0.24 g L⁻¹ for S. brasiliensis. Comparison with response surface methodology showed that both approaches provided strong predictive performance, although the statistical model predicted the optimum conditions more accurately. For S. boniae, however, the ANN-GA approach identified an alternative condition associated with lower nitrogen supplementation and higher experimental xylitol production. Given the limited dataset, this study should be regarded as a proof-of-concept for the application of data-driven optimization tools to xylitol fermentation. The results indicate that ANN-GA can complement classical statistical methods by helping to identify alternative operating conditions in bioprocess optimization. Full article

The jalapeño pepper (Capsicum annuum L.) is a crop of great economic and nutritional importance worldwide; however, increasing yield and quality under conditions of reduced synthetic inputs remains a significant challenge, mainly due to restrictions in plant nutrition and stress response capacity; in this context, plant-based biostimulants, such as Ricinus communis extracts, are of particular interest due to their potential to modulate plant metabolism, promote growth, and favor the accumulation of bioactive compounds. In this study, the effect of a foliar-applied biostimulant derived from a methanolic extract of Ricinus communis L. on the physiological, agronomic, and biochemical parameters of jalapeño peppers was evaluated under open field conditions. A randomized complete design with five treatments was established: three extract concentrations (T50: 50 mg L⁻¹, T75: 75 mg L⁻¹, and T100: 100 mg L⁻¹), a commercial biostimulant (Pepton 85/16 ^®), and an absolute control. Significant differences (α ≤ 0.05) were observed between treatments T50, T75, and T100 with the application of castor bean and the absolute control in stem diameter, fruit number, yield, and polar and equatorial fruit diameter, as well as phenols, flavonoids, and antioxidant capacity (ABTS and DPPH). The application of R. communis extract (T50, T75, and T100) significantly improved plant performance compared to the control, particularly in yield (up to 270%), fruit number (73%), shoot biomass (up to 38%), and root development (up to 32%). Furthermore, increases in chlorophyll content and in antioxidant-related compounds were observed, including phenols, flavonoids, ABTS, and DPPH (up to 17%). Spearman correlation analysis revealed strong associations between structural and metabolic variables, highlighting the relationship between stem diameter, fruit traits, and bioactive compound accumulation, as well as the link between chlorophyll content and reproductive performance. The ¹H NMR analysis indicated the presence of secondary metabolites such as ricin, unsaturated fatty acids, and phenolic compounds; however, their isolation and relationship with the biostimulant activity of the extract require further specific studies. Overall, foliar application of R. communis extract improved the growth, productivity, and biochemical attributes of jalapeño pepper, highlighting its potential as a sustainable alternative for crop management. Full article

Twenty strains of Schizophyllum commune from the BIOTEC culture collection were selected for this study. S. commune is characterized by white to gray fan-shaped caps with lobed margins and distinctive split gills. Phylogenetic analysis of combined LSU rDNA and ITS rDNA sequences data using maximum parsimony placed the fungi in a strongly supported clade with S. commune. All strains were primarily screened for exopolysaccharide (EPS) and biomass production using potato dextrose broth (PDB) and peptone yeast glucose medium (PYGM) in 250 mL flasks shaken at 200 rpm for 7 days. The results revealed three strains with high EPS production, each exceeding 2.3 g/L, namely MMCR00487, MMCR00474 and MMCR00256. These strains were selected for media optimization using a Plackett–Burman design. Among them, MMCR00256 exhibited the highest EPS yield of 8.34 ± 1.47 g/L, followed by MMCR00487 and MMCR00474. Therefore, the strain MMCR00256 was further optimized by central composite design. The results revealed that the optimized medium for MMCR00256 increased the production of EPS to 10.39 ± 1.69 g/L, with a biomass yield of 26.28 ± 1.63 g/L (395 mg/g). The 5 L bioreactor optimization tested two inoculum types (mycelial and pellet) and two media (CCD and estimated) using strain MMCR00256. The mycelial inoculum grown in the estimated medium produced the highest EPS yield of 8.37 ± 0.26 g/L after 3 days, with 13.56 ± 2.94 g/L biomass. In conclusion, this study demonstrates that S. commune MMCR00256, when cultivated using the estimated medium and mycelial inoculum, can achieve enhanced exopolysaccharide production with improved efficiency, highlighting its significant potential for the development of efficient and scalable schizophyllan production processes at the industrial scale. Furthermore, this study provides essential insights into the cultivation and optimization of schizophyllan in S. commune. Full article

The transition toward industrial-scale, year-round production of Pleurotus pulmonarius necessitates efficient and standardized spawn production. Liquid spawn technology plays a pivotal role in this process; however, recommended formulations and science-based quality criteria remain lacking. This study aimed to screen a high-performance liquid spawn medium and define key quality parameters for industrial application. Ten culture media formulations were evaluated to determine their effects on mycelial growth, as well as the subsequent yield and quality of fruiting bodies. The optimal formulation (Formula 4) contained glucose (1.6%), soybean meal (0.3%), corn flour (0.2%), peptone (0.2%), KH₂PO₄ (0.1%), and MgSO₄ (0.055%). The growth rhythm of the selected formulation was meticulously tracked, leading to the identification of a critical inoculation window between 4.75 and 5.5 days. Spawn within this window exhibited a mycelial biomass of 1.60~1.86 g/L, pellet diameter of 1.83~1.92 mm, pellet density of 12.25~13.75 per mL, and fermentation broth pH of 6.35~6.44, which were strongly correlated with peak yield (up to 284 g/bag) and premium-grade ratio (up to 87.97%). The multi-parameter composite standard is proposed as a practical tool for quality control in industrial fermenters, enabling precise harvest timing and ensuring the consistent, high-yield, and high-quality production of P. pulmonarius. Full article

Thraustochytrids are promising alternatives for the production of docosahexaenoic acid (DHA; C22:6 n-3), a long-chain polyunsaturated fatty acid with health benefits. For practical application of this oleaginous microorganism, an efficient cultivation method to enhance DHA production is required, which relies on several factors that support cell growth, lipid accumulation, and lipid turnover. In this study, the robust submerged fermentation of an acid- and high-temperature-tolerant strain of Aurantiochytrium limacinum was investigated. Under controlled temperature and acidic conditions (pH 4.5 and 30 °C), glucose and peptone were the best carbon and nitrogen sources for enhancing biomass and DHA production, respectively, with a glucose concentration of 60 g/L and a C/N ratio of 24 being optimal for DHA production. Applying an aeration rate of 2 vvm and an agitation speed of 300 rpm using a combination of a ring sparger and pitch-blade impeller in a stirred-tank bioreactor improved DHA production using intermittent fed-batch fermentation. The highest DHA titer was obtained at 3.01 g/L, and the DHA content in biomass was 10.69% (w/w) after intermittent feeding of cassava starch hydrolysate as the substrate. Full article

Cycloheptylprodigiosin is a promising anticancer candidate that induces cancer cell death accompanied by severe Golgi stress. Although the soybean oil-based optimized MB2216 medium produced a total prodiginine titer approximately three times that of the basal MB2216 medium, the overall production level remained limited. In addition, a substantial fraction of the pigments partitioned into floating oil droplets, hindering efficient recovery by simple centrifugation. In this study, a novel medium was rationally formulated based on genomic insights derived from homology analysis of conserved biosynthetic genes involved in cycloheptylprodigiosin production in Spartinivicinus ruber MCCC 1K03745^T. Sequential optimization through single-factor experiments, full factorial designs, steepest ascent experiments and response surface methodology identified an optimal medium consisting of peptone (5 g/L), yeast extract (1 g/L), peanut meal (7.611 g/L), and L-Proline (0.695 g/L) prepared in seawater at pH 7.6. Under the optimized conditions, the total prodiginine titer reached 53.33 mg/L, which was 11.37 times that of the basal MB2216 medium and 3.29 times that of the soybean oil-based MB2216 medium. Moreover, the pigment-associated biomass could be efficiently recovered by centrifugation. This study provides a genomics-informed strategy for improving prodiginine production in S. ruber and facilitates downstream pigment recovery. Full article

Dactylis glomerata is a globally important cool-season forage grass with high ecological and economic value. During field surveys conducted in three counties of the Ili region of Xinjiang, Zhaosu County, Tekes County, and Xinyuan County, a previously unreported root rot disease was observed on wild orchardgrass, with disease incidence ranging from 20% to 72%. The most severe symptoms were recorded in Zhaosu County. The pathogen was isolated and identified as Bipolaris sorokiniana based on morphological characteristics and multilocus phylogenetic analyses of ITS, GAPDH, and TEF gene sequences. The results of biological characteristics showed that the optimal conditions for mycelial growth were 25 °C, pH 7, continuous light for 24 h, potato sucrose agar (PSA) as the culture medium, soluble starch as the optimal carbon source, and peptone as the optimal nitrogen source. In vitro fungicide sensitivity assays indicated that all nine tested fungicides significantly inhibited mycelial growth of B. sorokiniana. Among them, difenoconazole exhibited the highest inhibitory activity, with an EC₅₀ value of 0.0706 mg·L⁻¹, followed by tebuconazole (EC₅₀ = 0.3606 mg·L⁻¹) and tetramycin (EC₅₀ = 0.6815 mg·L⁻¹). These findings provide a scientific basis for further studies on disease epidemiology, pathogenic mechanisms, and integrated management of this disease. Full article

Fish waste disposal poses significant environmental and economic challenges, limiting sustainability in the marine food industry. Hence, sustainable valorization strategies are needed to enhance resource recovery while minimizing waste. As an approach, this study aimed to evaluate the potential of converting chum salmon (Oncorhynchus keta) head (CSH) waste into a high-value peptone for microbiological applications. Various proteolytic enzymes were screened for CSH hydrolysis, among which Protamex achieved the highest hydrolysis and recovery rates. The resulting chum salmon head peptone (CSHP) exhibited favorable characteristics, including a low average molecular mass (557 Da) and a high amino nitrogen content (4.9%), outperforming commercial animal (AP) and vegetable (VP) peptones. To assess its biotechnological potential, CSHP was evaluated as a nitrogen source for recombinant protein production and supported higher expression of human superoxide dismutase (hSOD) and human growth hormone (hGH) in Escherichia coli BL21(DE3), compared with AP, VP, and Luria–Bertani (LB) media. Furthermore, life cycle assessment revealed a substantially lower carbon footprint for CSHP production than that of conventional peptone sources. These findings suggest that CSHP is a reliable and sustainable alternative to traditional peptones, offering both therapeutic and industrial applications while contributing to marine waste reduction and circular bioeconomy strategies. Full article