Biocatalysis and agricultural biotechnology最新文献

Biofilm plays a critical role in protecting the associated bacterial colonies. Citrus canker caused by Xanthomonas citri, resulted in remarkable yield reduction in citrus orchards. This study aims to evaluate the anti-biofilm properties of S. hortensis and B. subtilis extracts against X. citri. The antibacterial effects of both extracts were evaluated using the disk diffusion method and 96-well microdilution plates. Crystal violet and XTT procedures were employed to assess the inhibition of adhesion and antibiofilm effects of both extracts. The checkboard titration method was applied to determine the synergistic effects of the plant-bacterial extracts. The antibiofilm effects were confirmed by the light microscopy method. The results showed that the antibacterial and antibiofilm properties of both extracts varied. The MIC values of S. hortensis and B. subtilis extracts were 6.25 and 50 mg/ml, respectively. In these concentrations the inhibition of adhesion effects of S. hortensis and B. subtilis were 70% and 80%, whereas their antibiofilm effects were 60% and 72%. S. hortensis and B. subtilis extracts showed 63% and 76% antibiofilm activity, respectively, using the XTT test. The extracts showed synergistic effects, resulting in higher inhibition rates in combinatorial applications. Molecular docking results also confirmed that the secondary metabolites of S. hortensis could interact with different X. citri proteins differentially. Further large-scale studies on combinatorial antibiofilm effects of plant and bacterial extracts against citrus pathogens will provide new opportunities to develop safe and applicable reagents to control these destructive diseases.

Microcystinase (MlrA) is the most specific catalyst and the most efficient enzyme of known microcystins (MCs) detoxification pathways. Very recently, direct MlrA application has effectively degraded MCs within industrial processes, demonstrating MlrA application for sustainable in situ MCs remediation. Heterologous MlrA expression in cyanobacteria offers a unique opportunity, linking harmful MCs remediation with emerging cyanobacterial biotechnologies. Here, we first generate a novel Synechocystis sp. PCC 6803 (6803) using non-native trc promoter for MlrA expression. Whole-cell MlrA activity was comparable to previously described expression via native 6803 PcpcB₅₆₀ promoter, while cellular extracts of the new strain showed significantly higher MlrA yields (2–15 times, depending on the age of the cultures). Furthermore, efficiency of MlrA production under multiple photoautotrophic cultivation conditions varied, but was not improved by Na₂CO₃ supplementation nor under increased light, indicating the need to explore new photoautotrophic chassis for higher MlrA productivity.

Methods for MlrA stabilization are critical for industrial development, thus lyophilization of MlrA-enriched cellular extracts was explored. Recovered MlrA activity was not statistically different from initial MlrA activity following storage of lyophilized extracts at −20 °C for 20 weeks. In contrast, storage at 20 °C and storage of aqueous lysates at 4 °C resulted in progressive MlrA activity loss. Such stabilized lyophilizate may offer a checkpoint for further optimization of upstream processes (production), while expanding potential for downstream investigations (application), contributing simultaneously to novel MlrA-based MCs remediation approaches and to cyanobacterial biotechnology.

Digestate is a byproduct of anaerobic digestion (AD) where organic waste is converted into biogas, a clean source of energy. The growing interest in renewable energy and waste management has increased the number of AD plants worldwide in recent years. Therefore, the appropriate digestate management has shifted towards the concept of waste to products and the realization of a circular economy to maximize the benefits of AD plants as well as digestate valorization. The various properties of digestate such as organic matter, nutrient composition, moisture content, and plausible pollutants, determine its suitability for further application. Proper management and handling are required to minimize environmental risks and enhance the value of the digestate valorization. Instead, its use in conventional ways, novel strategies for digestate utilization are emerging to properly benefit and practically realize the biorefinery of AD plants at a large scale. Moreover, the proper knowledge of regulations and standards concerning the proper digestate utilization is required. This article summarizes the digestate properties and their factor affecting, digestate treatment technologies. The current digestate valorization practices have been discussed along with the focus on the novel and emerging practices. Most importantly, the regulations and standards followed around the globe have been majorly focused upon so that the environmental concerns arising due to its utilization should be taken care of well. Further, the challenges and future perspectives of digestate management and valorization are discussed to be understood for attaining a full circular economic concept in the AD plants at an industrial scale.

This research is centered on improving a xylanase enzyme derived from Myceliophthora heterothallica by expressing it in Pichia pastoris to enhance biomass hydrolysis. Lignocellulosic biomass holds significant potential for renewable applications in biofuels, chemicals, and pharmaceuticals. The study explores the impact of the choice of expression host on enzyme properties, specifically addressing challenges in thermostability by utilizing P. pastoris and leveraging its glycosylation capabilities. Previously expressed in Escherichia coli, the xylanase exhibited in this work cooperative kinetics, pH stability, and resistance to phenolic compounds. Gene integration and expression in P. pastoris were verified through PCR and activity assays. After 120 h of induction, an enzymatic activity of 48.8 U mL⁻¹ was obtained. Subsequent characterization revealed improved specific activity, substrate affinity, and optimal temperature compared to the enzyme expressed in E. coli. The enzyme exhibited excellent pH and temperature stability for industrial applications, maintaining over 90% of its activity within a pH range of 5.0–10.0 and remaining stable even after 90 min of incubation at 55 °C. It also demonstrated resistance to metal ions and responsiveness to phenolic compounds. These findings underscore the versatility of the recombinant xylanase from M. heterothallica expressed in P. pastoris, highlighting its potential as a valuable resource for biomass conversion. The study emphasizes the pivotal role of host choice in optimizing enzyme characteristics for industrial applications, underscoring the importance of employing heterologous expression systems, as demonstrated in this investigation.

The effects of moisture content of batter, air integration in batter, and temperature of tray dryer were studied on hardness, whiteness index, water absorption capacity, and oil uptake ratio of black gram nugget (bori), and it was optimized using response surface methodology. The optimized conditions were: moisture content 67.01 %, air incorporation 21.68 % (v/v) of batter and 60 °C temperature required to attain maximum whiteness index of 81.21, water absorption capacity 41.86 ml/min, minimum hardness value 44.59 N and oil uptake ratio 14 % of nuggets. Optimized black gram nuggets' carbohydrate, protein, fat, and ash contents were 65.49 %, 25.70 %, 1.45 %, and 1.87 %. HPLC analysis showed the presence of different antioxidants in it. The optimized black gram nuggets' color, texture, porosity, and diameter changes during cooking indicated good quality.

Considering various industrial applications of thermostable xylanases and scarcity of data available on xylan degradation potential of the Neobacillus species, this study was designed to characterize xylanase produced by the thermophilic strain of N. sedimentimangrovi UE25 using sugarcane bagasse as a carbon source. Xylanase was characterized by adopting a Central Composite design (CCD), which has not been reported earlier for this purpose. The enzyme exhibited thermal stability over a range of temperatures from 50 to 80 °C and its optimal activity was obtained at 65 °C and pH 4.0. The enzyme did not lose its activity for approximately 13 days when kept at 4 °C and retained 84% of its catalytic activity even after 2.5 h of incubation at 65 °C. Various metals and chemicals resulted in enhanced xylanase activity when mixed with this enzyme. Moreover, xylanase was purified by ion exchange chromatography, and its molecular weight was estimated to be ∼60 kDa. The purified xylanase was applied in a saccharification process to improve the total phenolic content (90 mg GAE/g) of the biomass of a halophytic plant, Ipomoea pes-caprae.

Globally the rate of melanoma skin cancer has increased in the recent years. Conventional treatments like chemotherapy, radiotherapy and surgery will damage the cancer cells and some healthy cells also in the body. These treatments are expensive and severe side effects on humans. Nanotechnology have recently been used in biological systems to enhance both reformative and translational therapies. In this study, we used binary solvent for preparation of plant extracts and phytosynthesized AgNPs. It is well known that AgNPs synthesized using green methods are preferred as eco-friendly, low cost, rapid and efficient process. For the assessment of the therapeutic activity of synthesized AgNPs, we proposed an in-vitro model of human melanoma skin cancerous cells (SK-MEL-3). The specific characteristics of AgNPs such as size, shape, distribution, crystalline structure etc. are examined before the medicinal application. In addition, we have done cytotoxicity analysis and apoptotic study to understand the morphological alteration in malignant cells.

With a growing global population, maintaining sufficient agricultural production is crucial. However, agriculture faces numerous challenges today, particularly due to the undeniable impacts of climate change, which are expected to intensify pest and disease pressures. The traditional approach to combat these phytopathological issues has relied on synthetic chemical pesticides. While their use has indeed increased productivity, it is also evident their detrimental and cumulative effects on the environment, and the current negative perception of the population toward these chemicals. In response, governments are prompting the search for alternatives to synthetic pesticides, through different policies, such as the strategy From Farm to Fork in the European Union, which aims to reduce the use of chemical pesticides by 50% by 2030, among other measures. At this point, seed extracts with biocidal activity are emerging as a viable option for the control and management of various pathogenic agents, such as harmful bacteria, fungal and oomycete pathogens, and plant-parasitic nematodes. Nevertheless, it is worth mentioning that most of the studies have been only conducted under highly controlled conditions. Thus, this line of research should be still more deeply developed, including proofs under field conditions, in order to become the extensive and widespread use of these bio-products a reality. In this review, we compile the main studies focused on the use of these compounds for phytosanitary purposes, describing and analysing the key metabolites, their composition, extraction processes and the mechanisms involved in their antagonistic effects. Additionally, we analyse the primary factors contributing to the limited adoption of these extracts in the field, such as the scarcity of studies under real conditions or the possible impact on non-target organisms, and discuss future prospects for their development.

The aim of the study was to isolate potential probiotic lactic acid bacteria (LAB) strains from the traditional fermented milk products, Chhurpi of the Sikkim Himalayan region and to prepare curd using mixed culture fermentation. A preliminary probiotic assessment of 110 LAB isolates including antimicrobial activity, bile and acid tolerance, surface hydrophobicity, auto-aggregation and co-aggregation, and adhesion to Caco-2 cells, was performed. Lactiplantibacillus plantarum strains N4, CHDE2, CHDE4, and SS22 demonstrated better viability in bile (0.3%) and acid (pH 2.5), adherence with hydrophobicity (13.93–92.85%), auto-aggregation (72.44–89.74%), adhesion to Caco-2 cells (45–73.61%) and antimicrobial activity against food borne pathogens. These strains were used for mixed culture fermentation with a previously screened curd forming strain Lactobacillus delbrueckii WS4. Curd produced using mixed culture fermentation of Lb. delbrueckii WS4 and the selected Lp. plantarum strains had a relatively higher acid production (pH 3.97–4.01), protein hydrolysis, and antioxidant activity. Further, mixed culture fermentation also resulted in the increase of HOCl scavenging activity (12.22–32.96%), myeloperoxidase (MPO) inhibition activity (22.38–42.94%) and angiotensin converting enzyme (ACE) inhibition (15.61–33.03%) as compared to that of WS4 fermentation (P < 0.05). This is the first report on identification of potential probiotic strains from the traditional fermented milk products of Sikkim and application in mixed culture fermentation with enhanced multifunctional potential.