Optimal Culture Research Articles

Copper Tolerance of Trichoderma koningii Tk10

Copper (Cu) is an essential micronutrient for all living organisms, serving as a cofactor for numerous enzymes. However, excessive copper concentrations can be harmful. To investigate copper tolerance in fungi, a copper-tolerant strain was isolated from soil and identified as Trichoderma koningii Tk10, with optimized culture conditions being established. Additionally, copper-related genes were analyzed through whole-genome sequencing. The results indicated that Tk10 exhibits a maximum copper tolerance of 5.4 mmol/L and a maximum adsorption rate of 51.5% under optimal cultivation conditions. Whole-genome sequencing revealed six genes associated with copper tolerance, including one superoxide dismutase gene, one peroxidase gene, and three catalase genes linked to copper stress. Furthermore, the enzyme activities of the catalase, superoxide dismutase, and peroxidase significantly increased, reaching levels that were 8.02, 4.12, and 3.88 times higher than those observed in the control group, respectively. A real-time quantitative PCR analysis indicated that three of these genes were significantly upregulated in response to copper stress. The findings of this study provide valuable insights into copper tolerance in filamentous fungi.

Heterologous Expression of Laccase1 from Cryphonectria parasitica in Saccharomyces cerevisiae

Laccases are enzymes capable of oxidizing phenolic compounds and are important tools in different industrial processes. Heterologous expression of laccases is of great interest in biotechnological applications but achieving high expression levels is challenging. Three different laccases have been identified in the chestnut blight fungus Cryphonectria parasitica, among which a tannic acid-inducible laccase (laccase3) was successfully expressed using Saccharomyces cerevisiae. To obtain high and stable expression of fungal laccases, we cloned the gene encoding an extracellular laccase (Laccase1) of C. parasitica into a yeast episomal vector, used the resulting vectors to transform S. cerevisiae, and optimized the culture conditions of the selected transformants for Laccase1 production. We also tested the significance of the signal peptide of Laccase1 in the secretion of expressed Laccase1 and compared it with the widely used rice amylase signal peptide. Among the four constructs tested using a yeast episomal vector, full-length Laccase1 containing an endogenous signal peptide, showed the highest laccase activity. Interestingly, the stability of the recombinant vector expressing laccase was lower than that of the mock transformant, suggesting a detrimental effect of the Laccase1-expressing vector on host cells. Thus, we optimized the culture conditions to produce Laccase1 and the resulting optimum culture conditions identified through one-factor-at-a -time (OFAT) were 2% sucrose; 3% yeast nitrogen base without amino acid; pH 5.0; and 30 °C. The laccase activity was found to be 2.2 U/mL in optimal culture conditions, resulting in a 6.5-fold increase compared to the conventional culture medium.

The design of the spheroids-based in vitro tumor model determines its biomimetic properties.

Cancer, one of the world's deadliest diseases, is expected to claim an estimated 16 million lives by 2040. Three-dimensional (3D) models of cancer have become invaluable tools for the study of tumor biology and the development of new therapies. The tumor microenvironment (TME) is a determinant of tumor progression and has implications for clinical therapies. Cancer-associated fibroblasts (CAFs) are one of the most important components of the TME. Modeling the interactions between cancer cells and CAFs in vitro can help to create biomimetic tumor equivalents for elucidating the causes of cancer growth and assessing the effectiveness of therapies. Here, we are investigated the effect of the mutual arrangement of tumor cells and fibroblasts on the formation of tumor models and their biomimetic properties. Pancreatic tumor models of three different designs were formed by the bioprinting method. Gelatin-alginate hydrogels with and without PANC-1 (pancreatic cancer) and NIH/3T3 (mouse fibroblasts) cells, as well as their homo- and heterospheroids, were used as bioink. To enable bioprinting, we have chosen the most suitable compositions of alginate and gelatin that provide both good printability and cell proliferation activity. We also have investigated the kinetics of spheroid formation to identify the optimal cultivation parameters for achieving spheroid sizes suitable for bioprinting. All tumor models remained viable for 3-4weeks. At the same time, the patterns of model development in the cultivation process and the biomimetic properties of the final tissue-engineered structures depended on the model design.

Diversidade genética das características de processamento do café em Coffea canephora

ABSTRACT: With advancements in coffee cultivation, several traits may be considered in selection of plants, which must exhibit a set of favorable characteristics. The outturn index, defined as the relationship between the mass of mature fruit and processed beans, emerges as a key factor influencing productivity. This study characterized the outturn over two harvests of 57 clones marketed in the public domain and 10 registered cultivars. The analysis considers the effects of genotypes, measurements, and genetic progress achieved through plant selection. According to the maturation cycle of each clone, washed samples of cherry coffee were collected considering a completely randomized factorial design for characterization of the effects of genotypes, years, and the genotype × years (GY) interaction. The drying, peeling, and the outturn index were individually assessed. Despite the significant effects of the GY interaction, genotypes demonstrated minimal alterations in their ranking across measurements. Clones with higher outturn, including LB30, BRS1216, LB12, N7, LB10, LB20, BRS3220, and AS5, exhibited an average outturn of 25.51%, reflecting a gain of 12.17%. Conversely, clones with lower outturn, such as BG180, GJ30, GJ20, AS7, AS10, P42, N1, and P60, had an average of 19.15%, indicating a reduction of 14.02% compared to the general mean. Analyzing the distribution of the outturn values, 19.4%, 62.7%, and 17.9% of genotypes were classified as high, medium, and low outturn, respectively, providing valuable insights for optimal cultivation strategies.

Enhancing green waste compost quality for stevia (Stevia rebaudiana) cultivation through the addition of vermicompost and pond sediment

As global waste management challenges grow and the demand for sustainable horticulture increases, green waste (GW) has emerged as a key resource for compost production. However, this kind of green waste compost (GWC) has numerous difficulties when employed directly because of its inherent limits. It includes poor bulk density, irregular nutrient content and inadequate porosity. This study was to investigate the impact of various ratios of vermicompost (VC; 0%, 10%, 20%) and pond sediment (PS; 0%, 10%, 25%) on GWC and their potential use as substrates for floriculture in order to get over these restrictions. The total fresh weight (TFW), total dry weight (TDW), and total chlorophyll (TChl) of stevia were measured, alongside a comprehensive analysis of the physicochemical properties of the enhanced substrate. TFW, TDW, and TChl of stevia in T5 were increased by 140%, 78%, and 30%, respectively, compared to the unmodified GWC. The optimal cultivation substrate for stevia was provided by the most comprehensive evaluation index, which reached 0.76. This study effectively utilized waste materials to improve the fertility and structure of the cultivation substrate, significantly enhancing nutrient uptake and promoting stevia growth and development, resulting in a dual improvement in yield and quality. Moreover, the study contributes to the creation of a more efficient and friendly horticultural ecosystem, demonstrating how waste can be converted into valuable resources and offering innovative solutions for waste management. These outcomes support sustainable development and optimize waste management strategies.

The Effect of Seasonal and Annual Variation on the Quality of Polygonatum Cyrtonema Hua Rhizomes.

This study aims to reveal the interannual and seasonal variations in functional components in Polygonatum cyrtonema Hua. rhizomes and evaluate whether the variations significantly affect the quality of rhizomes as a traditional Chinese herbal medicine. The interannual and seasonal variations in total flavonoid content and total saponin content were analyzed. The global dynamic variation in secondary metabolites in the rhizomes during a five-year growth period and in two traditional harvesting seasons were investigated based on metabolomics method. Results clearly showed that the functional components in P. cyrtonema rhizomes exhibited a significant increase in accumulation during the one- to four-year growth period and a significant decrease in accumulation during the four- to five-year growth period. The most active accumulation occurred during the three- to four-year growth period. Drastic variations in functional components occurred from spring to autumn. The significant interannual variation and drastic seasonal variation were strongly associated with the enrichment in some pathways related to the biosynthesis of secondary metabolites and the metabolisms of amino acids. The interannual and seasonal variations in functional components significantly affected the quality of P. cyrtonema rhizomes. The four-year-old rhizomes had the most superior quality due to their higher content of functional components and much more newly formed components. The rhizomes harvested in spring or autumn had unequal quality because of their significant differences in composition and content of functional components. Specifically, the rhizomes from spring contained more flavonoids, alkaloids, and phenolic acids, while those from autumn comprised more steroids. In conclusion, this study reveals that the interannual and seasonal variations in functional components can significantly affect the quality of P. cyrtonema rhizomes as a traditional Chinese herbal medicine. This study provides foundational insights and theoretical guidance for determining an optimal cultivation period to obtain medicinal rhizomes with superior quality. It also offers a strategy for harvesting medicinal rhizomes in two different seasons to achieve unequal quality.

Screening, Identification, and Optimization of Enzyme Production for Bacteria with High Efficiency of Bovine Blood Protein Degradation from Slaughterhouses

Blood waste originating from slaughterhouse activities in China is considered to be massive, and improper handling may cause epidemic diseases and environmental pollution. This research aimed to obtain a potential bacterial strain for blood protein degradation by isolating indigenous bacteria from slaughterhouses. Isolation was carried out by using dilution plate coating, while blood agar and casein plates were used to screen potential strains. Morphological, physiological, and biochemical characterizations, as well as 16S rRNA sequencing, were performed to identify the selected strain. The optimization of enzyme production was performed by using the Plackett–Burman test and response surface methodology. A strain coded NwMCC01910137 was isolated and screened to effectively degrade bovine blood protein and was identified as Bacillus subtilis. The optimum culture conditions for enzyme production included a fermentation temperature of 37.4 °C, an initial pH of 7.7, a soybean meal powder addition amount of 3.00% (w/v), a glucose level of 3.8% (w/v), a NaCl level of 0.3 g/L, a phosphate concentration of 2.5 g/L, an inoculum size of 2.5 g/L (4%), and a fermentation time of 48 h. Under the optimum condition, the strain showed enzyme activity of 166.83 U/mL. Hence, the isolated B. subtilis showed good activity in bovine blood protein degradation and has good application potential for slaughterhouse waste processing.

Kinetic Modelling of Ralstonia eutropha H16 Growth on Different Substrates

Due to environmental pollution and the depletion of fossil fuels, there is growing interest in the development and use of biofuels as environmentally friendly alternatives. One of the most promising biofuels is biohydrogen, hydrogen produced through sustainable processes using microorganisms such as bacteria and algae. One of the most interesting bacteria for hydrogen production is Ralstonia eutropha H16, known for its ability to produce oxygen-tolerant hydrogenases. These enzymes play a crucial role in biohydrogen metabolism and production. The aim of this work was to determine the optimal conditions (reactor type and synthetic medium composition) for the cultivation of R. eutropha H16. The culture media contained different concentrations of fructose and glycerol (mono- or double-substrate cultivation) and the experiments were carried out in a batch reactor. The initial experiments were carried out with 4 g/L fructose or glycerol in the culture medium at pH 7, T = 30 °C, and 120 rpm. The mathematical model, consisting of the growth kinetics (described by the Monod’s model) and the corresponding mass balances, was proposed. The developed model was validated using two independent experiments with different initial substrate concentrations: 2 g/L glycerol and fructose in one medium and 4 g/L fructose and 1 g/L glycerol in the second. In order to propose the optimal cultivation procedure for future research, the mathematical model simulations were performed for different reactor types (batch, fed-batch, and continuous stirred tank reactors) and different initial substrate concentrations. The most successful experiment was the one with 4 g/L glycerol, where γX = 0.485 ± 0.001 g/L of biomass was achieved. Further calculations showed that the most biomass would be produced at higher glycerol concentrations (at γG = 6.358 g/L, γX = 1.311 g/L should be achieved after 200 h of cultivation) and when using a fed-batch reactor (γX = 0.944 g/L after 200 h of cultivation).

Morphological and molecular identification of Schizophyllum commune causing storage bulb rot disease of Lanzhou edible lily in China and its biological characteristics.

Lily bulb rot disease has harmed edible lily in recent years, resulting in yield losses in China. As a results, both morphological and molecular techniques must be used to confirm the etiology of storage bulb rot disease on lily bulbs. Lily bulbs with indications of rot symptoms during storage were gathered in Lanzhou, Gansu Province, China. A strain was isolated and its morphologically characterized as a Schizophyllum commune specie. Pathogenicity tests further confirmed that the strain caused apparent S. commune symptoms on lily bulbs which were consistent with those seen in the field. The pathogenicity of S. commune to lily bulb was 100%, and morphological identification showed that the mycelia of the pathogen were white and villous, with septate, branched, and acicular bodies and obvious lock-shaped joints. The mycelia had uneven thickness, ranging from 1.03 to 3.06 μm, and turned gray-white at the later growth stage. Moreover, the pathogen formed a mycelial column on potato dextrose agar (PDA) medium, which formed a coral-like fruiting body primordium, which split, forming pileus for spore production. The spores were colorless and cylindrical, with an oblique tip and a size of 4.6-7.2 μm × 2.2-2.7 μm. The isolate was deduced as based on phylogenetic analysis with 2 genes (ribosomal DNA-ITS and LSU) as well as morphological characteristics and cultural features, the isolate was identified S. commune. Soluble starch, yeast extract, temperature of 30°C, pH 7, relative humidity of 100%, and complete dark were shown to be the optimum culture conditions for surface mycelium growth. In conclusion, this is the first report of S. commune causing bulb rot of edible lilies in China. The study provides a basis for more effective control strategies for lily bulb rot disease.

Harvesting the Future: AI Innovations in Agricultural Intelligence

Undoubtedly, Artificial Intelligence (AI) currently stands at the pinnacle of technological advancement, permeating various sectors such as manufacturing, marketing, industry, and even gaming, where its impact is profound. However, amidst this widespread adoption, agriculture emerges as a significant concern. Examining the extent of farming dependencies globally reveals the substantial investment pouring into the sector for acquiring new machinery, seeds, and equipment. This paper aims to delve into such statistics and studies, shedding light on how prominent regions are leveraging these technologies to offer cost-effective and efficient solutions for farmers, facilitating optimal cultivation of their fields.

Delineation Protocol of Agricultural Management Zones (Olive Trees and Alfalfa) at Field Scale (Crete, Greece)

This study proposes a three-stage, flexible and adaptable protocol for the establishment of field-scale agricultural management zones (AMZs) using remote sensing, ground truthing (apparent electrical conductivity and soil sampling), the IRRIGOPTIMAL® system and machine learning. The methodology to develop this protocol was applied to olive and alfalfa plots in Heraklion (Crete, Greece) to monitor soil and plant responses for the period 2022–2024. However, the actual time for the implementation of this protocol varies between 3 and 6 months. The first step of this protocol involves the use of soil and vegetation reflectance mapping (moisture, photosynthetic activity) by satellites and unmanned aerial systems, together with geophysical electromagnetic induction mapping (apparent electrical conductivity) to verify soil variability, which is strongly linked to the delineation of management zones. In the second step, a machine learning-based prediction of the spatial distribution of soil electrical conductivity is made, considering the data obtained in the first step. Furthermore, in the second step, the IRRIGOPTIMAL® system provides real-time monitoring of a variety of weather (such as air temperature, dew point, solar radiation, relative humidity, precipitation) and soil (temperature, moisture) parameters to support the optimal cultivation strategy for the plants. Once the data have been analysed, the soil variability of the plot and the presence or absence of cultivation zones are determined and the decision on the cultivation strategy is made based on targeted soil sampling and further soil analyses. This protocol could contribute significantly to the rational use of inputs (water, seeds, fertilizers and pesticides) and support variable rate technology in the agricultural sector of Crete.

Comprehensive cultivation of the broiler gut microbiota guides bacterial isolation from chickens.

Chicken gut microbiota plays an important role in maintaining their physiological health. However, the cultivability of chicken gut microbiota is not well understood, limiting the exploration of certain key gut bacteria in regulating intestinal health and nutritional metabolism. This study aimed to examine the cultivability of chicken cecal microbiota and to provide guidance for future chicken gut microbiota cultivation. A total of 58 different culture conditions were applied to culture broiler cecal microbiota, and the culture-dependent (CD; pooled colonies form each plate) and culture-independent (CI; broiler cecal contents) samples were collected for 16S rRNA gene sequencing and microbial analysis. The CD methods detected higher microbial richness (3,636 vs 2,331 OTUs) than CI methods, and the recovery rates of bacterial OTUs and genera reached 43.6% and 68.9%, respectively. The genera of Bacteroides (19.9%), Alistipes (11.0%) and Barnesiella (10.7%) were highly abundant detected by CI methods, however, there occupied a small proportion (<1.0%) of total cultured microbiota in CD methods. We then developed reference figures and tables showing optimal cultivation conditions for different gut bacteria taxa. Moreover, 81 different lactic acid bacteria strains covering 5 genera were isolated, and 15 strains had less than 97.0% similarity to known bacteria in the national center for biotechnology information (NCBI) online database. Overall, this study provides preliminary guidance in culturing specific gut microbiota from chickens, which will contribute to future studies to characterize the biological functions of key microbes in chicken nutritional metabolism and health.

Effect of NAA and TDZ on In Vitro Plantlet Induction of Cryptocoryne Wendtii “Brown”

The exotic aquatic plant, Cryptocoryne wendtii “Brown”, can develop into an economic crop with a continually increasing export value. Thailand is unable to produce to meet the demand. Therefore, this experiment aimed to study the optimum concentrations of growth regulators on plantlet induction. The sterile apical bud was cultured on semi-solid MS media (Murashige and Skoog, 1962) supplemented with 1-naphthaleneacetic acid (NAA) at 0, 0.1, 0.2, 0.3 mg/L and thidiazuron (TDZ) at 0, 1, 2, 3 mg/L. In the sixth week, the semi-solid MS medium which contains 0.1 mg/L NAA and 2 mg/L TDZ showed the maximum new plantlets (67.92±19.61 plantlets/explant), leaves (67.42±19.46 leaves/explant) and height (28.65±1.55 mm./plantlet), had the highest average significance (P&lt;0.05). Micropropagation of C. wendtii “Brown” in optimum culture medium could increase the volume within a shorter period and enhances the potential for quality and value-added to aquatic plant production.

Light Intensity Effects on Productivity and Post-Harvest Quality in Perilla frutescens Cultivated in CEA

Leafy vegetables, mainly lettuces, are currently the main crop cultivated in controlled environment agriculture (CEA), including vertical farming and plant factories. There is a rising demand to expand this portfolio with a wider variety of underutilized edible plants containing various bioactive compounds and sensory properties seeking to enrich human diets. However, the optimal cultivation conditions for these underutilized plants significantly differ from those optimized for lettuce, basil, and other popular CEA crops. Therefore, this study aims to explore the impacts of light-emitting diode (LED) lighting intensity (photosynthetic photon flux density, PPFD) on green leaf Perilla frutescens cultivated in CEA. Plants were grown under four levels of LED lighting PPFDs from 150 to 300 µmol m−2s−1 for 4 weeks. Plant biomass productivity, soluble sugar contents, antioxidant properties (DPPH, ABTS free radical scavenging activities, FRAP antioxidant power), and total contents of phenolic compounds in leaves were evaluated at harvesting time. Further, harvested plant material was stored in the dark, at +6 °C, and the water content, water loss and transpiration rate, leaf sugar contents, and antioxidant properties were monitored 1, 3, and 5 days after harvesting. The summarized data suggest that higher cultivation lighting PPFD results in better harvest quality preservation during post-harvest storage.

Batch cultivation of Chlorella vulgaris and simultaneous treatment of restaurant wastewater

BackgroundThe rapid growth of restaurants due to the changing lifestyle has imposed unnecessary impacts on environmental sustainability following an increased generation of restaurant wastewater (RWW). RWW contains alarming concentrations of fats, oils, and greases (FOG), chemical oxygen demand (COD), biochemical oxygen demand (BOD), and nutrients, including nitrogen and phosphorus. Microalgae are known to be able to treat wastewater and provide simultaneous production of biomass and other valuable metabolites (e.g., lipids, proteins, and carotenoids). Numerous studies have been reported on treating various types of wastewater using microalgae. However, studies still need to be reported on treating RWW using microalgae collected from grease traps. MethodsThis research aims to determine the potential of the freshwater microalgae Chlorella vulgaris (Chlorella vulgaris) in treating RWW-containing pollutants (COD, BOD, FOG) and nutrients (TN, TP, AN, K) via optimal autotrophic cultivation conditions (i.e., pH, temperature, light intensity, and aeration). Significant FindingsThe conditions for the batch scale cultivation of Chlorella vulgaris opted as an autotrophic mode with a temperature of 25 °C, aeration of 3 litres per minute supplemented with 3 % CO2 (v/v), and an irradiance range of 80–150 μmol/m2/sec. Maximum specific growth rate and biomass productivity achieved were 0.14 day-1 and 42 mg/l/d, respectively. The maximum pollutant removal efficiency was 98 % for COD, 98.5 % for BOD, 96.8 % for FOG. While the nutrient uptake achieved was 99.7 % for total nitrogen (TN), 99.9 % for ammoniacal nitrogen (AN), 99.9 % for total phosphorus (TP), and 97.8 % for potassium (K). Therefore, this study shall provide an alternative potential solution by proposing treatment using microalgae and cultivating it with RWW. No study has been reported to date using freshwater microalgae Chlorella vulgaris to evaluate its potential in removing pollutants, nutrients, and FOG in RWW collected from GGI. The removal efficiencies indicated that the RWW acclimatised well with Chlorella vulgaris, thus providing an environmentally sustainable and economically viable treatment method.

Effect of Altitude and Dose of Nitrogen Fertilizer on the Growth of Ruskus Plants (Ruscus hypophyllum L.)

Ruscus hypophyllum is an ornamental plant leaves that serve as cut foliage and herbal medicine. It is growth very slow, only two rods per month, so that is necessary to optimization cultivation, one of them with treatment of altitude (environment) and fertilization This research aimed to determine the effect of nitrogen fertilizer dose altitude for growth of ruskus. The study was compiled using a factorial design nested prepared using RAK and repeated 3 times. The first factor is altitude of 500 m asl (T1), 800 m asl (T2) and 1500 m asl (T3). The second factor is nitrogen fertilization: 0 g/plant (N0), 2 g/plant (N1), 4 g/plant (N2) and 6 g/plant (N3). Based of the research, there was a very real interaction between altitude and dose of nitrogen fertilization on some parameters of observations include: shoot length, number of buds, young leaf chlorophyll, number of roots and root length. The best treatment was a combination of T3N1 (altitude 1500 m asl and nitrogen fertilizer 2 g / plant), separately treatment of altitude very significant effect on the parameters of the number of leaves and shoots appear, and the best treatment is T3 (altitude 1500 m asl). There is a very real correlation between treatment of observations include: the number of long shoots with leaves (0.75), long shoots with the number of shoots (0.64), long shoots with a number of roots (0.79), long shoots with long roots (0, 84), number of leaves with the number of shoots (0.76), young leaf chlorophyll with long roots (0.75) and the number of roots with root length (0.65). The results of path analysis, there are two parameters that have a direct influence on the observation that young leaf chlorophyll (0.094) and the old leaf chlorophyll (0.335).

High-throughput optimization of organic carbon provision strategies enables enhanced arachidonic acid production in novel microalgae

BackgroundMicroalgae are potential sustainable resources for the production of value-added chemicals that can be used as biofuels, pharmaceuticals, and nutritional supplements. Arachidonic acid (ARA), a omega-6 fatty acid, plays a crucial role in infant development and immune response, and can be used in cosmetics and pharmaceuticals. Demand for industrial-scale ARA production is continuously increasing because of its broad applicability. To address this demand, there has been a significant shift towards microorganism-based ARA production. To accelerate large-scale ARA production, it is crucial to select suitable strains and establish optimal culture conditions.ResultsHere, we isolated a novel microalga Lobosphaera incisa CFRC-1, a valuable strain that holds promise as a feedstock for ARA production. Optimal cultivation conditions were investigated using a high-throughput screening method to enhance ARA production in this novel strain. Out of 71 candidates, four organic carbon substrates were identified that could be utilized by L. incisa CFRC-1. Through flask-scale verification, fructose was confirmed as the optimal organic carbon substrate for promoting microalgal growth, total lipid accumulation, and ARA production. Subsequently, we investigated appropriate substrate concentration and cultivation temperature, confirming that the optimal conditions were 30 g L− 1 of fructose and 27 ℃ of temperature. Under these optimized conditions, biomass and ARA production reached 13.05 ± 0.40 g L− 1 and 97.98 ± 7.33 mg L− 1, respectively, representing 9.6-fold and 5.3-fold increases compared to the conditions before optimization conditions. These results achieved the highest biomass and ARA production in flask-scale cultivation, indicating that our approach effectively improved both production titer and productivity.ConclusionsThis study presents a novel microalgae and optimized conditions for enhancing biomass and ARA production, suggesting that this approach is a practical way to accelerate the production of valuable microalgae-based chemicals. These findings provide a basis for large-scale production of ARA-utilizing microalgae for industrial applications.

Prediction of optimal bioremediation conditions for petroleum hydrocarbon contaminated soil by automated machine learning-based analysis

Petroleum hydrocarbons (PH) contaminated soil has become a long-standing problem. By employing microorganisms, plants, or microbial enzymes, bioremediation has the potential to detoxify and remove contaminants from soil and water environments. Given the complexity of environmental variables, it is significant to build a robust model for predicting optimal remediation conditions. In this study, H2O automated machine learning (AutoML) successfully predicted the effects of 8 variables on the remediation efficiency of PH-contaminated soil without human intervention. It was suggested that composting bioremediation and biochar immobilization prompted PH degradation, while bioaugmentation and phytoremediation exhibited lower removal efficiency. Moreover, PH concentration and cultivation period, rather than PH type and soil physicochemical properties, significantly influenced PH bioremediation. Specifically, remediation efficiency enhances when the PH concentration is below 5000 mg/kg and then decreases as it keeps ascending at a gradual rate. Furthermore, optimal cultivation period in the range of 20–40 days is conducive to PH biodegradation. This work successfully demonstrated that AutoML could be a valuable tool for predicting optimal remediation conditions of PH -contaminated soil.

Synergistic interaction between Azotobacter and Pseudomonas bacteria in a growth-stimulating consortium

Intensifying agricultural production involves an active use of agrochemicals, which results in disrupted ecological balance and poor product quality. To address this issue, we need to introduce biologized science-intensive technologies. Bacteria belonging to the genera Azotobacter and Pseudomonas have complex growth-stimulating properties and therefore can be used as a bioproduct to increase plant productivity. We aimed to create a growth-stimulating consortium based on the strains of the genera Azotobacter and Pseudomonas, as well as to select optimal cultivation parameters that provide the best synergistic effect. We studied strains Azotobacter chroococcum B-4148, Azotobacter vinelandii B-932, and Pseudomonas chlororaphis subsp. aurantiaca B-548, which were obtained from the National Bioresource Center “All-Russian Collection of Industrial Microorganisms” of Kurchatov Institute. All the test strains solubilized phosphates and produced ACC deaminase. They synthesized 0.98–1.33 mg/mL of gibberellic acid and produced 37.95–49.55% of siderophores. Their nitrogen-fixing capacity ranged from 49.23 to 151.22 μg/mL. The strain had high antagonistic activity against phytopathogens. In particular, A. chroococcum B-4148 and A. vinelandii B-932 inhibited the growth of Fusarium graminearum, Bipolaris sorokiniana, and Erwinia rhapontici, while P. chlororaphis subsp. aurantiaca B-548 exhibited antagonism against F. graminearum and B. sorokiniana. Since all the test strains were biologically compatible, they were used to create several consortia. The greatest synergistic effect was achieved by Consortium No. 6 that contained the strains B-4148, B-932, and B-548 in a ratio of 1:3:1. The optimal nutrient medium for this consortium contained 25.0 g/L of Luria-Bertani medium, 8.0 g/L molasses, 0.1 g/L magnesium sulfate heptahydrate, and 0.01 g/L of aqueous manganese sulfate. The optimal cultivation temperature was 28°C. The microbial consortium created in our study has high potential for application in agricultural practice. Further research will focus on its effect on the growth and development of plants, in particular cereal crops, under in vitro conditions and in field experiments.

Optimized biosynthesis of lytic enzymes by special Trichoderma citrinoviride

The use of Trichoderma filamentous fungi in the wide concept of biocontrol is still a highly relevant topic. The multifaceted nature of their impact on phytopathogenic microorganisms results from the species diversity and complexity of their antagonistic action. The presented research aimed to determine optimal cultivation conditions of two T. citrinoviride strains for the biosynthesis of major enzymes especially those involved in the biocontrol process. Culture conditions were optimized using a three-factor Box-Behnken design to maximize the yield of chitinase and lichenase. The following independent variables were included in the model: incubation temperature, initial pH, and supplementation with fungal biomass. As a result of statistical optimization, unprecedented activities of extracellular lytic enzyme were achieved. For the B1 and B3 strains, the optimal pH was 3.5 or 7.5, respectively, in the determination of chitinase biosynthesis. It was similar for the biosynthesis of β-1.3 and β-1.4 glucanases, but at higher cultivation temperature. The exception was the B3 strain, for which the optimal pH in glucanase biosynthesis was 5.5. The most stimulating culture temperature in the process of chitinase biosynthesis and β-1.3 and β-1.4 glucanases was above 25 °C. In that, the levels of enzyme biosynthesis and corresponding composition culture environment were confirmed to be strain-dependent.