Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be ...degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV) or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W) plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Biochar prompted an increase growth and nutritional status of maize plant.•In the soil, he raised water retention and reduced bulk density.•High biochar doses improved soil fertility.•But, the water ...retention gains promoted by biochar did not overcome the water stress.
Studies on biochar application in agriculture are broad, but the effects are variable and depend on the type of plant, biochar properties, and application rate, as well as some soil characteristics and environmental conditions. This study aimed to assess the effect of applying different doses of biochar with two particle sizes on the physical and chemical characteristics of a Typic Haplustox, sandy loam, and on the growth and physiological characters of maize plants, under two soil moisture conditions. The study was conducted in a greenhouse, using two biochar particle sizes (2.0−0.5 and < 0.5 mm), at six doses (0, 5, 10, 20, 40 and 60 g kg−1) and two water conditions (with and without drought stress). The plant characters assessed were height, stem diameter, leaf area, shoot fresh and dry weight, and nutritional status. Leaf relative water content, photosynthesis, and stomatal conductance were evaluated under drought stress. The soil attributes studied were density, porosity, water retention curve, and hydrophobicity, in addition to chemical characterization. There were no statistical differences between the two biochar particle sizes, except for bulk density and microporosity. Under adequate water conditions, and two doses of biochar applied to the soil increased photosynthesis, stomatal conductance, and leaf relative water content in the sewn corn. In the soil, biochar raised water retention and the micropore/macropore ratio and reduced bulk density, in addition to improving fertility. High biochar doses improved soil fertility as well as plant nutritional status and development. The increased water retention as a consequence of biochar amendment was not sufficient to overcome drought stress problems in the soil.
Brazilian coffee production relies on the cultivation of Coffea arabica and Coffea canephora. Climate change has been responsible for the decreasing yield of the crops in the country yet the ...associated microbial community can mitigate these effects by improving plant growth and defense. Although some studies have tried to describe the microorganisms associated with these Coffea species, a study that compares the microbiome on a wider spatial scale is needed for a better understanding of the terroir of each coffee planting region. Therefore, our aim was to evaluate the microbial communities harbored in soils and fruits of these Coffea species in four Brazilian floristic domains (Amazon, Atlantic Forest Caatinga, and Cerrado). One hundred and eight samples (90 of soil and 90 of fruits) were used in the extraction and sequencing of the fungal and bacterial DNA. We detected more than 1000 and 500 bacterial and fungal genera, respectively. Some soil microbial taxa were more closely related to one coffee species than the other species. Bacillus bataviensis tends to occur more in arid soils from the Caatinga, while the fungus Saitozyma sp. was more related to soils cultivated with C. arabica. Thus, the species and the planting region (floristic domain) of coffee affect the microbial composition associated with this crop. This study is the first to report microbial communities associated with coffee produced in four floristic domains that include sites in eight Brazilian states. Data generated by DNA sequencing provides new insights into microbial roles and their potential for the developing more sustainable coffee management, such as the production of biofertilizers and starter culture for fermentation of coffee cherries.
Edaphoclimatic conditions, planting altitudes, soil, the microbiome of plants and fruits, genotypes, and postharvest processing are variables that contribute to the chemical and sensory quality of ...the coffee. Thus, the objective of this study was to evaluate the impacts of planting altitude and fermentation of fruits on the chemical and sensory quality of the coffee using Nuclear Magnetic Resonance (NMR) and Linear Discriminant Analysis (LDA). Cherry coffees were harvested in eight points of altitudes between 826 and 1078.08 m. A completely randomized design with e planting altitudes, five fermentation processes, and five repetitions was performed. Lipids, trigonelline, citrate, and malate were the compounds that most contribute to the chemical discrimination of coffee in the altitudes below 969 m. While, in the high altitudes (> 1000 m), this discrimination was due to the HMF, quinic acid, caffeine, and formic acid, and the global notes of coffee beverages were higher than 80 points. In fermented coffee, the LDA of the chemical data indicates the formation of five clusters, showing how the compounds can suffer changes depending on the form of processing used in coffee. The best score of beverage was observed in samples of 1078.08 m under dry fermentation and only in samples of 969 m was observed a significant difference in the sensory score between spontaneous fermentation and induced fermentation. Thus, coffee sensory scores were dependent on planting and fermentation methods and NMR and LDA techniques proved important in chemical and sensory discrimination of coffees.
The quality of the coffee beverage is related to the chemical, physical, and sensory attributes of the coffee beans that vary with the geographic location of the crop, genetic factors, and ...post‐harvest processing. So, the objective of this study was to evaluate the genetic divergence of 27 genotypes of Coffea canephora using the volatile compounds and sensory attributes profile to select genotypes that produce a coffee beverage with high sensory quality. This genetic diversity was estimated from the Euclidean distance matrix using non‐standard data and the Unweighted Pair‐Group Method Using Arithmetic Averages (UPGMA). The 2‐furyl‐methanol, 4‐ethenyl‐2‐methoxyphenol, furfural, 5‐methylfurfural, methylpyrazine, and 2,6‐dimethylpyrazine were predominating volatile compounds in the genotypes. The sensory attributes had a positive Pearson's correlation with the total score. The volatile compounds had a different relative contribution to the genetic divergence between the genotypes of C. canephora. The 4‐ethenyl‐2‐methoxyphenol, 2‐furyl‐methanol, and furfural were volatile compounds that most contributed to the formation of the groups in the UPGMA dendrogram. The relative contribution of sensory attributes to dissimilarity among genotypes was 6.42% to 20.20%. Therefore, this study verified the relative contribution of volatile compounds, in specially 4‐ethenyl‐2‐methoxyphenol, 2‐furyl‐methanol, and furfural, and sensory attributes (flavor, mouthfeel, and bitterness/sweetness) to the genetic divergence between the genotypes of the three clonal varieties. Thus, this work points out compounds that positively contribute to the sensory quality of the Conilon coffee beverage.
In this study, we evaluated the growth of Pleurotus ostreatus PLO6 using oxo-biodegradable plastics as a carbon and energy source. Oxo-biodegradable polymers contain pro-oxidants that accelerate ...their physical and biological degradation. These polymers were developed to decrease the accumulation of plastic waste in landfills. To study the degradation of the plastic polymers, oxo-biodegradable plastic bags were exposed to sunlight for up to 120 days, and fragments of these bags were used as substrates for P. ostreatus. We observed that physical treatment alone was not sufficient to initiate degradation. Instead, mechanical modifications and reduced titanium oxide (TiO2) concentrations caused by sunlight exposure triggered microbial degradation. The low specificity of lignocellulolytic enzymes and presence of endomycotic nitrogen-fixing microorganisms were also contributing factors in this process.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The majority of the textile dyes are harmful to the environment and potentially carcinogenic. Among strategies for their exclusion, the treatment of dye contaminated wastewater with fungal extract, ...containing lignin peroxidase (LiP), may be useful. Two fungi isolates, Pleurotus ostreatus (PLO9) and Ganoderma lucidum (GRM117), produced the enzymatic extract by fermentation in the lignocellulosic residue, Jatropha curcas seed cake. The extracts from PLO9 and GRM117 were immobilized on carbon nanotubes and showed an increase of 18 and 27-fold of LiP specific activity compared to the free enzyme. Also, LiP from both fungi extracts showed higher Vmax and lower Km values. Only the immobilized extracts could be efficiently reused in the dye decolourization, contrary, the carbon nanotubes became saturated and they should be discarded over time. This device may offer a final biocatalyst with higher catalytic efficiency and capability to be reused in the dye decolourization process.
We studied the biodegradation of green polyethylene (GP) by Pleurotus ostreatus. The GP was developed from renewable raw materials to help to reduce the emissions of greenhouse gases. However, little ...information regarding the biodegradation of GP discarded in the environment is available. P. ostreatus is a lignocellulolytic fungus that has been used in bioremediation processes for agroindustrial residues, pollutants, and recalcitrant compounds. Recently, we showed the potential of this fungus to degrade oxo-biodegradable polyethylene. GP plastic bags were exposed to sunlight for up to 120 days to induce the initial photodegradation of the polymers. After this period, no cracks, pits, or new functional groups in the structure of GP were observed. Fragments of these bags were used as the substrate for the growth of P. ostreatus. After 30 d of incubation, physical and chemical alterations in the structure of GP were observed. We conclude that the exposure of GP to sunlight and its subsequent incubation in the presence of P. ostreatus can decrease the half-life of GP and facilitate the mineralization of these polymers.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Lignocellulosic raw materials have been widely studied for obtaining bioproducts. Pretreatments for delignification, uncertainties in feedstock composition, long hydrolysis times, and large ...quantities of expensive enzymes are factors that limit fermentable sugar production. Statistical optimization can help adjust these limiting factors and variables of enzymatic saccharification. This study aimed to optimize conditions for fermentable sugar production using wheat bran,
Botrytis ricini
URM 5627 endoglucanase, and Box–Behnken experimental design, a response surface methodology. A zymographic assay in polyacrylamide gel was stained with Congo red after hydrolysis. Enzymatic activity measurements indicated enzyme stability at different temperatures (− 20 °C and 6 °C) and periods (up to 120 days). Wheat bran was characterized using Fourier transform infrared spectroscopy (FTIR) before and after enzymatic saccharification. Saccharification time, substrate load, and enzyme load were optimized using the Box–Behnken design. The zymogram demonstrated a single activity band around 39 kDa, the molecular weight of
B. ricini
URM5627 endoglucanase. Enzyme activity was preserved at 78.78% and 86.08% after storage for 120 days at − 20 °C and 6 °C, respectively. FTIR analyses showed cellulose delignification and loosening after enzymatic action. Maximum production of reducing sugars (116.93 mg g
−1
) occurred when conditions were maintained at the central point of planning (8 h, 2% substrate load, and 4% enzyme load). The enzyme isolated from
B. ricini
was stable in solid medium and in stored form, and could saccharify wheat bran without pretreatments. High yield of reducing sugars and proximity between predicted and real values demonstrated effectiveness of statistical optimization in saccharification of lignocellulosic biomass.
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