Search Results (158)

The anaerobic co-digestion of agricultural residues emerges as a promising strategy for energy recovery and nutrient recycling within circular agricultural systems. This study aimed to optimize co-digestion parameters for vinegar residue (VR) and cattle manure (CM) using an orthogonal experimental design. Three key variables were investigated which are the co-substrate ratio (VR to CM), feedstock-to-inoculum (F/I) ratio, and total solids (TS) content. Nine experimental combinations were tested to evaluate methane yield, feedstock degradation, and digestate characteristics. Results showed that the optimal condition for methane yield comprised a 2:3 co-substrate ratio, 1:2 F/I ratio, and 20% TS, achieving the highest methane yield of 267.84 mL/g volatile solids (VS) and a vs. degradation rate of 58.65%. Digestate analysis indicated this condition generated the most nutrient-rich liquid digestate and solid digestate, featuring elevated N, P, and K concentrations, acceptable seed germination indices (GI), and moderate humification levels. While total nutrient content did not meet commercial organic fertilizer standards, the digestate is suitable for direct land application in rural settings. This study underscores the need to balance energy recovery and fertilizer quality in anaerobic co-digestion systems, providing practical guidance for decentralized biogas plants seeking to integrate waste treatment with agricultural productivity. Full article

This study presents the development and optimization of a functional soy sauce fermented with Cordyceps militaris (C. militaris), a medicinal fungus known for its high cordycepin and polysaccharide content. Using C. militaris as the sole starter culture, the process aimed to improve both nutritional and functional properties. Response surface methodology was employed to optimize the entire fermentation process. During the koji stage, temperature, aeration, and inoculum concentration were adjusted to maximize protease activity and cordycepin production. In the fermentation stage, temperature, brine concentration, and water-to-material ratio were optimized to increase amino acid nitrogen and bioactive compound levels. Under optimal conditions (24 °C, 679.60 LPM aeration, 9.6% inoculum for koji; 32 °C, 12% brine, 1.53:1 water-to-material ratio for fermentation), the resulting soy sauce contained 1.14 ± 0.05 g/100 mL amino acid nitrogen and 16.88 ± 0.47 mg/100 mL cordycepin. Compared with traditionally fermented soy sauce, the C. militaris product exhibited a darker color, enhanced umami taste, and a distinct volatile profile featuring linoleic acid, methyl palmitate, and niacinamide. These results demonstrate the feasibility of using C. militaris in soy sauce fermentation and its potential as a novel functional condiment with improved bioactivity and sensory quality. Full article

Monitoring pH and acidity during yoghurt fermentation is essential for product quality and process efficiency. Conventional measurement methods, however, are invasive and labour-intensive. This study developed artificial neural network (ANN) models to predict pH and titratable acidity during yoghurt fermentation using CIELAB colour parameters (L, a*, b*). Reconstituted milk powder with 12% total solids was prepared with varying protein levels (4.2–4.8%), inoculum concentrations (1–3%), and fermentation temperatures (36–44 °C). Data were collected every 10 min until pH 4.6 was reached. Forty models were trained for each output variable, using 90% of the data for training and 10% for validation. The first two phases of the fermentation process were clearly distinguishable, lasting between 4.5 and 7 h and exceeding 0.6% lactic acid in all treatments evaluated. The best pH model used two hidden layers with 28 neurons (R² = 0.969; RMSE = 0.007), while the optimal acidity model had four hidden layers with 32 neurons (R² = 0.868; RMSE = 0.002). The strong correlation between colour and physicochemical changes confirms the feasibility of this non-destructive approach. Integrating ANN models and colourimetry offers a practical solution for real-time monitoring, helping improve process control in industrial yoghurt production. Full article

This study investigated the quality evolution of soybean products (soymilk, tofu, dried bean curd) through mixed-strain fermentation with Lacticaseibacillus rhamnosus CICC 6151 and Saccharomyces cerevisiae AS2.400 under optimized conditions (7% inoculum, pH of 5.2, 85 °C/50 min thermal treatment). Physicochemical, structural, and microbial dynamics were systematically analyzed. Key results demonstrated that probiotic tofu exhibited superior water-holding capacity (82% WHC vs. 65% in traditional variants) and enhanced protein retention (Δ + 2.4% during storage), linked to microbial-mediated structural stabilization. Mixed fermentation induced substrate competition (S. cerevisiae biomass: OD₅₆₀ of 1.2 at 10 h vs. L. rhamnosus OD₆₀₀ of 1.0 at 25 h; ANOVA p < 0.001), driving pH-dependent protein network formation (isoelectric precipitation at pH of 4.8 ± 0.1) and volatile profile divergence (PCA explained 82.2–89.1% of variance). Probiotic variants maintained chromatic stability (ΔE < 15 vs. traditional ΔE > 23) and textural integrity (23% lower deformation under compression), correlated with secondary structure preservation (β-sheet increased by 10% in FTIR analysis). These findings establish synergistic microbial–metabolic regulation as a strategy for developing functional bean products with enhanced nutritional and sensory properties. Full article

Untreated olive oil mill wastewater (OOMW) from conventionally farmed olives was used in bread production to create a new functional product. Two types of bread were developed with 50% OOMW (EXP-1) and 100% OOMW (EXP-2) replacing water. Two leavening processes were tested: sourdough inoculum (S) vs. biga-like inoculum (B), with controls (CTR) without OOMW addition. The doughs were monitored throughout the acidification process by measuring pH, total titratable acidity, and the development of key fermentative microorganisms. To assess the hygienic quality during fermentation, plate count techniques were employed. After baking, the breads were evaluated for various quality parameters, including weight loss, specific volume, crumb and crust colors, image analysis, and the presence of spore-forming bacteria. Volatile compounds released from the breads were identified using solid-phase microextraction coupled with gas chromatography–mass spectrometry (SPME-GC/MS). Polyphenolic compounds were analyzed via liquid chromatography–mass spectrometry (LC-MS). To assess the functional properties of the final products, the breads were homogenized with synthetic human saliva and subjected to in vitro digestion. OOMW did not significantly affect the growth of yeasts and lactic acid bacteria (LAB) or the acidification process. However, in terms of the specific volume and alveolation, breads from the S process and OOMW had poor quality, while those from the B process had better quality. Experimental breads (EXP_B-1 and EXP_B-2) contained higher levels of alcohols (especially ethanol and isobutyl alcohol), carbonyl compounds (like benzaldehyde), esters (such as ethyl caproate and ethyl caprylate), and terpenes. OOMW introduced phenolic compounds like hydroxytyrosol, coumaric acid, caffeic acid, and trans-hydroxycinnamic acid, which were absent in CTR_B breads. Functionalization of EXP_B-1 and EXP_B-2 breads was demonstrated by a 2.4- and 3.9-fold increase in Trolox equivalents, respectively. However, OOMW did not reduce post-prandial hyper-glycemia, as starch digestibility was similar between CTR_B and EXP_B breads. The sensory analysis, which focused solely on the visual, structural, and olfactory characteristics of the breads, excluding taste testing to prevent potential health risks from residual pesticides, showed a high appreciation for EXP_B-1 and EXP_B-2 breads, scoring higher than CTR_B in the overall assessment. Full article

Yogurt is a highly consumed dairy product valued for its nutritional and probiotic properties. Its production involves the use of lactic acid bacteria, which drive biochemical transformations during fermentation. Optimizing fermentation time without compromising yogurt quality is essential for improving processing efficiency. Pulsed electric fields (PEFs) constitute a promising technology that stimulates microbial activity. In this study, a yogurt starter inoculum suspended in milk (IM) with different fat content (0.5–2.8%) was treated with low-intensity PEFs (1 kV/cm, 800–1600 µs) to enhance fermentation kinetics. pH, soluble solids, lactose, lactic acid, and riboflavin concentrations were monitored during 6 h, comparing PEF-treated IM (PEF-IM) and untreated IM (C-IM). PEF-treatments applied to IM reduced the fermentation time of inoculated milk by 4.3–20.4 min compared to C-IM. The lowest fermentation time (5.1 ± 0.16 h) was observed in milk added with PEF-IM (2.8% fat) treated at 1 kV/cm for 1600 µs. Milk inoculated with PEF-IM exhibited enhanced lactose consumption (1.6–3.1%) and higher lactic acid production (7.2%) than milk with C-IM. Riboflavin concentration (0.9–7%) decreased between 2 and 4 h, but it stabilized at the end of fermentation. Obtained results suggest that PEFs promote reversible electroporation in microbial cells, facilitating nutrient uptake and acidification, making it a promising assisted-fermentation approach to improve yogurt production. Full article

The composting sector plays a crucial role in the urban waste management system and is essential for advancing towards a circular economy. All organic matter can be entirely recovered from waste collection, except for the extraneous fractions present as impurities. In the studied waste composting plant, three fractions are produced: >50 mm (waste not idoneous for compost), <12 mm (suitable for compost market) and 50–12 mm (overflow). The latter is used as inoculum and therefore recirculates many times, reducing the sizes of its constituents, which are mainly plastic films falling into the lower class <12 mm, where they are concentrated. The goal of this study is to reduce the quantity of undesirable materials present in the 50–12 mm class in order to increase the quality of the compost produced. For this reason, a compost characterization was carried out and a plant solution was proposed: the inclusion of a mesh conveyor belt, with beater rollers and an aspiration system at the end. The fine organic material passes through the mesh sieve, and it is moved apart from the overflow material, in which the light plastics are aspirated. More than 10% of the overflow weight is recovered as clean compost, with very low percentages of undesired remaining. A reduction in plastic impurity of 75% is reached. Full article

Plumbagin is an important naphthoquinone with potent anticancer properties besides multitudinous uses in healthcare. It is produced in a limited number of species and families but mostly in the roots of Plumbaginaceae family members. The biosynthetic pathway and the genes that regulate plumbagin synthesis are not completely known, but details of these are being revealed. Several species, including Plumbago, Drosera, and others, are being uprooted for the extraction of plumbagin by pharmaceutical industries, leading to the destruction of natural habitats. The pharmaceutical industry is therefore facing an acute shortage of plant material. This necessitates enhancing the accumulation of plumbagin using suspensions and hairy roots to meet market demands. Many factors, such as the aggregate size of the inoculum, stability of the culture, and the sequential effects of elicitors, immobilization, and permeabilization, have been demonstrated to act synergistically and markedly augment plumbagin accumulation. Hairy root cultures can be used for the large-scale production, growth, and plumbagin accumulation, and the exploration of their efficacy is now imperative. The secretion of compounds into the spent medium and their in situ adsorption via resin has remarkable potential, but this has not been thoroughly exploited. Improvements in the quality of biomass, selection of cell lines, and production of plumbagin in bioreactors have thus far been sporadic, and these parameters need to be further exploited. In this review, we report the advances made relating to the importance of stable cell line selection for the accumulation of compounds in long-term cultures, hairy root cultures for the accumulation of plumbagin, and its semicontinuous production via total cell recycling in different types of bioreactors. Such advances might pave the way for industrial exploitation. The steps in the biosynthetic pathway that are currently understood might also aid us in isolating the relevant genes in order to examine the effects of their overexpression or heterologous downregulation or to edit the genome using CRISPR-Cas9 technology in order to enhance the accumulation of plumbagin. Its potential as an anticancer molecule and its mode of action have been amply demonstrated, but plumbagin has not been exploited in clinics due to its insolubility in water and its highly lipophilic nature. Plumbagin-loaded nanoemulsions, plumbagin–silver, or albumin nanoparticle formulations can overcome these problems relating to its solubility and are currently being tried to improve its bioavailability and antiproliferative activities, as discussed in the current paper. Full article

The banana pseudostem weevil (BPW), Odoiporus longicollis (Oliver), is one of the most destructive pests of bananas that is seriously affecting the yield and quality of bananas. We isolated pathogens from banana pseudostem weevils in Xishuangbanna and Dongchuan, Yunnan, China, and explored their biological characteristics. The pathogenicity of the strains was verified through laboratory and greenhouse inoculation experiments. The results showed that four strains of fungi were identified and confirmed as Beauveria caledonica (Bc) via ITS-rDNA sequencing. Optimal in vitro culture conditions were found to be a photoperiod of 24 h light, 25 °C temperature, and 18 days on potato dextrose agar (PDA) medium with insect meal. Under these conditions, the Cs-1 strain achieved a colony diameter of 65.17 ± 0.74 mm and spore production of 1.24 × 10⁸ cfu/cm². The Cs-1 strain had the shortest lethal time (LT₅₀) of 9.36 days at an inoculum of 1.00 × 10⁹ cfu/mL, with a lethality of 86.67% after 20 days. The Cs-3 strain showed 77.78% lethality at 1.00 × 10⁸ cfu/mL after 20 days. Despite variations in virulence, lethality did not correlate with major cuticle-degrading enzymes. The Cs-3 strain demonstrated effective biocontrol in greenhouse tests. Banana plants suffered significant damage without Bc-treated BPW, while the treated plantlets thrived. The mortality rate reached 82.78% after 35 days. This study marks the first identification of these entomopathogenic fungi (EPF) in Yunnan, China, highlighting B. caledonica’s potential for biocontrol application. Full article

In vitro cultivation of arbuscular mycorrhizal fungi (AMF) is challenging due to their biotrophic symbiosis. The principal aim of this study was to demonstrate the effect of establishing in vitro dual cultures of arbuscular mycorrhizal fungi (AMF) inoculated on Swietenia macrophylla (mahogany) roots on plant growth. Furthermore, it was sought to demonstrate that plant colonization by Glomeromycota can be achieved with a replicable protocol. This study established monoxenic cultures of carrot (Daucus carota) Ri T-DNA ROC inoculated with Glomus sp. on two-compartment plates. At 75 days, hyphal growth reached 223.93 mm in the root compartment and 103.71 mm in the hyphal compartment. Spores produced in vitro measured 26.14 ± 1.70 µm, smaller than ex vitro spores (101.2 ± 4.22 µm). Rhodotorula mucilaginosa was isolated from cultures and appeared to stimulate hyphal growth and root–fungal contact. From these cultures, a dual culture of mahogany inoculated with Glomus sp. was established. No significant differences were observed between inoculated and non-inoculated plants in stem length, root length, root number, or leaf number at 30 days. Spore production ranged from 10,166 to 27,696 per plate, averaging 14,795 ± 3301, with hyphal lengths of 3655.46 ± 308.75 mm. Hyphal development included running and branching patterns, with solitary and clustered spores. Spore diameter averaged 27.68 ± 3.85 µm. Arbuscular colonization reached 41.49% at 30 days and 52.13% at 75 days, exceeding rates reported for other culture systems. Monoxenic cultures are a reliable, aseptic source of high-quality inoculum, supporting biofertilizer production and biotechnological applications. These methods provide valuable tools for studies involving AMF, such as those demonstrated with mahogany. Full article

Bacillus velezensis is an effective biocontrol bacterium, with its microbial pesticides showing promise in biological control. In this study, we optimized the medium and conditions for fermenting strain F0b, developed a wettable powder formulation, and assessed its efficacy against Botrytis cinerea. We screened carriers, wetting agents, dispersants, and UV protectants compatible with F0b, determining the optimal ratio and dosage. The best medium for F0b fermentation included rice flour (3.472%), ammonium chloride (4.898%), and disodium phosphate (1.871%). The ideal fermentation conditions were a 20% inoculum volume, 40 °C temperature, 80% sterile water, and a 72 h fermentation time, yielding a viable count of 1.33 × 10¹⁰ CFU/mL. The final formulation contained 54.7% Bacillus velezensis dried powder, 27.3% kaolinite carrier, 16% wetting agent (3:7 ratio of sodium dodecyl sulfate to sodium lignin sulfonate), and 2% ascorbic acid as a UV protectant. All quality indicators met national standards, with a viable bacteria concentration of 7 billion CFU/g. Field trials showed that the F0b wettable powder effectively controlled Botrytis cinerea, with a disease index significantly lower than the control group. Control efficacy ranged from 50.58% to 73.14% over 7 to 14 days, demonstrating the commercial potential of this formulation. Full article

Fusarium avenaceum is the predominant fungal pathogen responsible for root rot in Angelica crops and poses a serious threat to their commercial quality and yield in China. This fungus produces enniatin B (ENN B), a toxin that could be a pathogenicity and virulence factor in plant–pathogen interactions. Yet whether ENN B exacerbates host infection and the onset of root rot in Angelica spp. caused by F. avenaceum is surprisingly understudied. Pathogenicity assays revealed that ENN B co-inoculation with F. avenaceum significantly increased the root rot disease index in Angelica sinensis from 83.33% (pathogen alone) to 92.86% (p < 0.05). Toxin degradation experiments showed that the bacteria Paenibacillus polymyxa and Bacillus tequilensis were capable of degrading 60.69% and 70.02% of ENN B, respectively. Response surface optimization (24.5 °C, 22.01 mg/L ENN B, 0.99% inoculum) enhanced degradation by B. tequilensis to 81.94%, a 11.74% improvement. Three ester compounds were identified by LC-HRMS as potential degradation products of ENN B. In planta trials demonstrated that the disease index was 50.01% for the group co-inoculated with ENN B degradation products and F. avenaceum, a 42.85% reduction compared to the group co-inoculated with ENN B and F. avenaceum. This study provides a new microbial strategy for controlling root rot in Angelica crops from a mycotoxin degradation perspective, which can be applied to promote sustainable agricultural production. Full article

This study developed an inoculum culture for semi-controlled coffee fermentation using lactic acid bacteria (LAB) and yeast, with coffee production by-products as carbon sources. The viability of the inoculum was optimized by using a mixture design to vary the proportions of coffee pulp (CP) and wastewater (CWW) in 0.25 increments; as a process variable, fermentation time ranged from 36 to 48 h for LAB and 12 to 36 h for yeast. Soluble solids (SS), pH, and titratable acidity (TA) were monitored, and the response variable was the variation in microbial viability. The optimized inoculums were used for coffee fermentation alone and in combination, and fermentation parameters and sensory evaluation were measured. The optimal by-product combination for LAB inoculum was 100% CP, with a 48 h fermentation, reaching a maximum of 7.8 × 10⁷ CFU/mL. The optimal formulation for yeast was 100% CWW for 36 h, achieving a maximum concentration of 8.3 × 10⁸ CFU/mL. Experimental results for both inoculums were fit to a quadratic statistical model with R² of 0.84 and 0.88 and Adj-R² of 0.77 and 0.83 for LAB and yeast, respectively. The optimized inoculums produced high sensory scores, particularly in balance, fragrance, and acidity. Using mixed inoculums, we achieved the highest fragrance/aroma score (8.25) and an improved balance, attributed to higher TA and lower pH, which are linked to enhanced flavor complexity. This demonstrates that by-product-based inoculums can not only increase microbial viability but also improve the sensory quality of coffee, supporting sustainable practices in coffee processing. Full article

The potential presence of toxic compounds in the digestate obtained from the anaerobic digestion of biodegradable waste restricts its application as a biofertilizer for soil conditioning and plant growth enhancement. The aim of this study was to assess digestate quality in terms of plant nutrient composition by evaluating the effects of activated carbon supplementation, inoculum source, and total solids content in the anaerobic digestion medium. The anaerobic digestion of food waste was conducted over a 60-day period at 25 °C in a 2.5 L bioreactor. The results demonstrated that inoculum diversity significantly impacted the digestate composition, particularly the zinc nutrient, with a p-value of 0.0054. This suggests that microbial diversity influences the valorization of organic waste into biofertilizer. However, the effects of inoculum diversity on other nutrients, aside from zinc, were not significant due to substantial interaction effects. Furthermore, assessing the impact of activated carbon supplementation proved challenging, as it was analyzed as part of a subset of the other two factors. The results of the digestate composition analysis indicated that activated carbon supplementation exhibited some influence on nutrient composition, necessitating further research to elucidate its significance. The findings of this study may contribute to enhancing the quality of digestate as a biofertilizer. Full article

The development of plant-growth-promoting bacteria (PGPB) is one of the important research topics in agricultural microbiology. Four bacterial isolates that exhibited nitrogen fixation, phosphate and potassium solubilization, as well as indole-3-acetic acid (IAA) and siderophore production abilities, were selected from biogas residue, namely BR-1, BR-16, BR-17, and BR-44. According to morphological and molecular biological identification, BR-1, BR-16, BR-17, and BR-44 belonged to Bacillus subtilis, Bacillus cereus, Bacillus megaterium, and Bacillus subtilis, respectively. The four functional strains were combined into a composite microbial community. The optimal media were peptone (15 g/L), sucrose (10 g/L), and KCl (2 g/L); the optimal incubation conditions were an initial pH of 7.0, a volume of 47 mL/250 mL, an inoculum size of 6% v/v, an incubation temperature of 31 °C, a shaking speed of 205 r/min, and an incubation period of 20 h, as determined through a single factor test and the response surface methodology (RSM). In the optimized process, a liquid bacterial inoculant with an OD₆₀₀ of 1.866 was obtained, with an effective viable count of 8.955 × 10⁹ CFU/mL. A solid bacterial inoculant was prepared by using bran as a substrate, and its effective viable count was 1.11 × 10⁹ CFU/g. The application of the bacterial inoculants promoted the growth of watermelon, increased the photosynthetic efficiency and yield, and improved fruit quality. This study provides a theoretical basis and technical support for the development and application of microbial inoculants. Full article