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The biocontrol strain Pseudomonas putida IsoF, which was isolated from a tomato rhizosphere, is a known N-acyl-homoserine lactone (AHL) producer with only one LuxI/LuxR-like quorum-sensing (QS) system. The production and degradation of AHLs were analysed in different growth phases of the bacterium. Using the analytical tools of ultra performance liquid chromatography and high resolution MS, it was possible to determine not only the various AHLs synthesized over time but also their degradation products. 3-oxo-decanoyl-homoserine lactone was found to be the dominant AHL, which reached its maximum in the early logarithmic growth phase. Although the pH of the medium was neutral, the AHLs were degraded thereafter rapidly to the corresponding homoserines and other metabolites. The proposed lactonase gene of P. putida IsoF could not be identified, because it is apparently quite different from hitherto described lactonases. The analytical data were used to calculate the rates and thresholds of AHL production by mathematical modelling, allowing quantitative predictions and a further understanding of the QS-based regulations in this bacterium. This study, combining microbiological, chemical and mathematical approaches, suggests that AHL degradation is an integral part of the whole autoinducer circuit of P. putida IsoF.

Packaged fruit produces a net accumulation of ethylene, the number of fruits affecting the peak and rate of accumulation. This study developed a model for quantifying net ethylene production using data from various tomato cultivars and packaging quantities. The ethylene accumulation was best described by the pseudo-first-order kinetic behavior, with peak ethylene concentrations ranging from 1.7 to 6.43 µL/L, depending on fruit mass and cultivars. The developed model was further simulated to estimate the dynamics of ethylene concentration in packaging with ethylene scavengers, estimating the amount of ethylene scavenger needed to extend tomato shelf life. Three scavenger adsorbents, Z-KMnO 4 , Basolite, and NZ-Ch, were evaluated. The simulations showed that Z-KMnO 4 was more effective in reducing ethylene concentration, compared to Basolite and NZ-Ch and that use of 1 g of Z-KMnO 4 delayed ripening of 1 kg of Optima tomatoes by 28.23 h. This study emphasized the importance of understanding dynamics in ethylene concentration in developing packaging systems with ethylene scavengers. A minimum ethylene concentration was necessity for ripening. An exact amount of ethylene scavenger was needed to ripen the packaged fruits and extend the shelf life to the targeted value. Model simulation can be used for designing optimal ethylene scavenger systems to achieve desired ripening within the targeted shelf life. A customized packaging solution can be designed based on specific cultivar needs and packaging quantities.

The proof-of-the-concept of application of low-temperature food waste biochars for the anaerobic digestion (AD) of food waste (the same substrate) was tested. The concept assumes that residual heat from biogas utilization may be reused for biochar production. Four low-temperature biochars produced under two pyrolytic temperatures 300 °C and 400 °C and under atmospheric and 15 bars pressure with 60 min retention time were used. Additionally, the biochar produced during hydrothermal carbonization (HTC) was tested. The work studied the effect of a low biochar dose (0.05 gBC × gTSsubstrate−1, or 0.65 gBC × L−1) on AD batch reactors’ performance. The biochemical methane potential test took 21 days, and the process kinetics using the first-order model were determined. The results showed that biochars obtained under 400 °C with atmospheric pressure and under HTC conditions improve methane yield by 3.6%. It has been revealed that thermochemical pressure influences the electrical conductivity of biochars. The biomethane was produced with a rate (k) of 0.24 d−1, and the most effective biochars increased the biodegradability of food waste (FW) to 81% compared to variants without biochars (75%).

The growing demand for efficient and cost-effective industrial proteases has intensified bioprospecting efforts in diverse ecosystems as a strategy to identify microorganisms with enhanced enzymatic performance. This study aimed to isolate, identify, and evaluate aerobic protease-producing bacteria from animal-protein matrices and water sources collected across the three continental regions of Ecuador, and to assess their suitability for industrial enzyme production A total of 34 bacterial strains were isolated and taxonomically assigned to the orders Enterobacterales, Pseudomonadales, and Bacillales. Proteolytic activity was evaluated using azocasein and casein assays after cultivation in an optimized medium containing 1% soybean paste as an inducer at 37 °C and 120 rpm for 72 h. Enterobacter cloacae (BC, pork), Bacillus paramycoides (P2, snook), and Pseudomonas aeruginosa (CH1, chontacuro) were identified as the most active protease producers from the Andean (Sierra), coastal (Costa), and Amazon regions, respectively. Production kinetics revealed marked strain-dependent differences. BC and P2 reached maximum proteolytic activity on day 4 followed by a decline, whereas CH1 peaked on day 2 and maintained stable activity over time, indicating superior enzymatic stability. Partial purification by gel-filtration chromatography (Sephadex G-100) yielded fractions with enhanced proteolytic activity, while SDS-PAGE analysis confirmed successful enrichment of protease-containing fractions. Overall, the results demonstrate that ecological origin strongly influences protease production and stability, and identify Pseudomonas aeruginosa CH1 as a particularly promising candidate for industrial applications requiring robust and sustained proteolytic activity.

Background Ganoderic acids (GAs), derived from the medicinal mushroom Ganoderma lucidum , possess anticancer and other important pharmacological activities. To improve production of GAs, a homologous farnesyl diphosphate synthase (FPS) gene was overexpressed in G. lucidum . Moreover, the influence of FPS gene overexpression on GA production was investigated by developing the corresponding mathematical models. Results The maximum levels of total GAs and individual GAs (GA-T, GA-S, and GA-Me) in the transgenic strain were 2.76 mg/100 mg dry weight (DW), 41 ± 2, 21 ± 5, and 28 ± 1 μg/100 mg DW, respectively, which were increased by 2.28-, 2.27-, 2.62-, and 2.80-folds compared with those in the control. Transcription levels of squalene synthase (SQS) and lanosterol synthase (LS) genes during GA biosynthesis were upregulated by 2.28- and 1.73-folds, respectively, in the transgenic G. lucidum . In addition, the developed unstructured models had a satisfactory fit for the process of GA production in submerged cultures of G. lucidum . Analysis of the kinetic process showed that FPS gene overexpression had a stronger positive impact on GA production compared with its influence on cell growth. Also, FPS gene overexpression led to a higher non-growth-associated-constant β (1.151) over the growth-associated-constant α (0.026) in the developed models. Conclusions FPS gene overexpression is an effective strategy to improve the production of GAs in G. lucidum . The developed mathematical models are useful for developing a better GA production process in future large-scale bioreactors.

Background Bacterial genomes often encode structures similar to phage capsids (encapsulins) and phage tails which can be induced spontaneously or using genotoxic compounds such as mitomycin C. These high molecular-weight (HMW) putative antibacterial proteins (ABPs) are used against the competitive strains under natural environment. Previously, it was unknown whether these HMW putative ABPs originating from the insect pathogenic Gram-positive, spore-forming bacterium Brevibacillus laterosporus ( Bl ) isolates (1821L, 1951) are spontaneously induced during the growth and pose a detrimental effect on their own survival. Furthermore, no prior work has been undertaken to determine their biochemical characteristics. Results Using a soft agar overlay method with polyethylene glycol precipitation, a narrow spectrum of bioactivity was found from the precipitated lysate of Bl 1951. Electron micrographs of mitomycin C- induced filtrates showed structures similar to phage capsids and contractile tails. Bioactivity assays of cell free supernatants (CFS) extracted during the growth of Bl 1821L and Bl 1951 suggested spontaneous induction of these HMW putative ABPs with an autocidal activity. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of spontaneously induced putative ABPs showed appearance of ~ 30 kDa and ~ 48 kDa bands of varying intensity across all the time intervals during the bacterial growth except in the initial hours. Statistically, spontaneously induced HMW putative ABPs of Bl 1951 exhibited a significant decrease in the number of viable cells of its producer strain after 18 h of growth in liquid. In addition, a significant change in pH and prominent bioactivity of the CFS of this particular time period was noted. Biochemically, the filtered supernatant derived from either Bl 1821L or Bl 1951 maintained bioactivity over a wide range of pH and temperature. Conclusion This study reports the spontaneous induction of HMW putative ABPs (bacteriocins) of Bl 1821L and Bl 1951 isolates during the course of growth with potential autocidal activity which is critically important during production as a potential biopesticide. A narrow spectrum of putative antibacterial activity of Bl 1951 precipitate was found. The stability of HMW putative ABPs of Bl 1821L and Bl 1951 over a wide range of pH and temperature can be useful in expanding the potential of this useful bacterium beyond the insecticidal value.

This study assessed the impact of rumen ‘fluid not adapted’ (FNA) and of rumen ‘fluid adapted’ (FA) to three additives on in vitro kinetics of gas production and end products of fermentation. The experiment was performed according to a Latin Square Design of 4 cows and 4 experimental periods. The dry cows received a total mixed ration designed for lactating cows without (control) or with 1 g/d of one of three additives (allyl-sulphide, cinnamaldehyde, limonene) that were selected for their known effects on rumen fermentation. The collected rumen fluids (FNA and FA, respectively) were used as inoculum of 4 consecutive in vitro incubations (1 for each experimental period) adding or not adding 30 mg of one of the three pure compounds. The incubations were performed using a commercial equipment to evaluate the kinetics of gas production and collect the end products of fermentation. The results indicated that FA did not influence any fermentation parameters compared to FNA. However, when allyl-sulphide was added in vitro, the effects of this compound tended to be more pronounced with FA than with FNA. This experiment highlights that the three tested pure additives, which show activity on in vitro fermentations, can alter the in vitro activity of rumen fluid collected from cows fed with these compounds. Therefore, the administration of pure additives directly to the cows can influence the rumen microbial activity and the response of in vitro experiments.

The process of anaerobic digestion used for methane production can be enhanced by dosing various additive materials. The effects of these materials are dependent on various factors, including the processed substrate, process conditions, and the type and amount of the additive material. As part of the study, three different materials—iron powder, lime, and milled porous ceramic—were added to the 30-day anaerobic digestion of the brewer’s spent grain to improve its performance. Different doses ranging from 0.2 to 2.3 gTS × L−1 were tested, and methane production kinetics were determined using the first-order model. The results showed that the methane yield ranged from 281.4 ± 8.0 to 326.1 ± 9.3 mL × gVS−1, while substrate biodegradation ranged from 56.0 ± 1.6 to 68.1 ± 0.7%. The addition of lime reduced the methane yield at almost all doses by −6.7% to −3.3%, while the addition of iron powder increased the methane yield from 0.8% to 9.8%. The addition of ceramic powder resulted in a methane yield change ranging from −2.6% to 4.6%. These findings suggest that the use of additive materials should be approached with caution, as even slight changes in the amount used can impact methane production.

Abstract The nutritive value of the carob fruits harvested from ten different geographic regions of the North and the Center of Tunisia was assessed on the basis of chemical composition and in vitro rumen fermentation kinetic. Results showed that the chemical composition (ash, crude protein, fat, and sugar) of carob pods was highly influenced by geographic origin. Neutral detergent fiber varied from 24.37 to 35.58 g/100 g DM, acid detergent fiber from 13.24 to 25.15 g/100 g DM, and acid detergent lignin from 4.72 to 11.09 g/100 g DM. Total phenol, flavonoids, and condensed tannin contents varied from 2.55 to 6.84 g gallic acid equivalents (GAE)/100 g DM, from 74.89 to 276.51, and from 0.23 to 1.63 mg catechin equivalents (CE)/100 g DM, respectively. The samples varied widely in asymptotic gas production (66.6–86.34 ml/300 mg DM). The calculated metabolizable energy and digestible organic matter contents of carob pods ranged from 65.09 to 84.65% and 9.84 to 12.82 MJ/kg DM, respectively.

This study aimed to investigate the effect of tannin extract from mangosteen peel (MANGTAN) in soybean meal on the in vitro gas production kinetics, degradability, and intestinal digestion of proteins using a three-step in vitro procedure. A completely randomized design (CRD) was used as the experimental design with nine treatments. The dietary treatments involved spraying different amounts of mangosteen peel extract (MANGTAN; mL) onto soybean meal (SBM; gDM) in a mixture, with the ratios being 0:100, 5:100, 10:100, 15:100, 20:100, 25:100, 30:100, 35:100, and 40:100. It was found that MANGTAN did not influence the gas production kinetics (P < 0.05). However, MANGTAN did influence the gas production from the immediately soluble fraction (a), which was found to have the highest gas volume at the level of 15 mL of MANGTAN/100 gDM of soybean meal. In vitro dry matter at 12 h decreased when using 5–40 mL of MANGTAN/100 gDM of soybean meal. Organic matter degradability at 12 and 24 h was reduced when using MANGTAN on soybean meal (P < 0.05). Analysis of crude protein degradability using a three- step in vitro procedure found that increasing the levels of 5 to 40 mL of MANGTAN/100 gDM of soybean meal resulted in reduced crude protein degradation in the rumen (24 h), but the intestinal digestion of proteins was improved. In addition, the levels of 15 mL of MANGTAN/100 gDM of soybean meal and above influenced the decrease in total protein degradation (P < 0.05). Based on the results, using 15 mL of MANGTAN/100 gDM of soybean meal could modify gas production kinetics, increase in vitro degradability, protect ruminal crude protein degradability, and increase intestinal crude protein degradability.