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Although addition of pyrolyzed organic materials (biochars) to soil generally results in increased growth and physiological performance of plants, neutral and negative responses have also commonly been detected. Toxicity of organic compounds generated during pyrolysis, sorbed by biochars, and then released into the soil solution, has been implicated as a possible mechanism for such negative effects. Conversely, water-soluble biochar constituents have also been suggested to have "hormetic" effects (positive effects on plants at low concentrations); however, no specific compounds responsible have been identified. We investigated the relative phytotoxicity—and possible hormetic effects—of 14 organic compounds common in aqueous extracts of freshly produced lignocellulosic biochars, using seed germination bioassays. Of the compounds examined, volatile fatty acids (VFAs: acetic, propionic, butyric, valeric, caproic, and 2-ethylbutyric acids) and phenol, showed acute phytotoxicity, with germination-based ED50 values of 1–30 mmol L−1, and 2-ethylbutyric acid showed ED50 values of 0.1–1.0 mmol L−1. Other compounds (benzene, benzoic acid, butanone, methyl salicylate, toluene, and 2,4-di-tert-butylphenol) showed toxic effects only at high concentrations close to solubility limits. Although phytotoxic at high concentrations, valeric and caproic acid also showed detectable hormetic effects on seedlings, increasing radicle extension by 5–15% at concentrations of ~ 0.01–0.1 mmol L−1. These data support the hypothesis that VFAs are the main agents responsible for phytotoxic effects of lignocellulosic biochar leachates, but that certain VFAs also have hormetic effects at low concentrations and may contribute to positive effects of biochar leachates on early plant development in some cases. Highlights: 151 compounds were identified in leachates from 13 biochars. Among common compounds, volatile fatty acids (VFAs) and phenol showed the most pronounced phytotoxic effects. Some VFAs also had hormetic effects, enhancing radicle extension growth at low concentrations. Effects were consistent among test plant species but the smallest-seeded species showed the highest sensitivity. [ABSTRACT FROM AUTHOR]

Monilinia laxa is one of the most destructive fungal pathogens causing brown rot, blossom blight and spur infection on stone fruits such as peach, nectarine, apricot, cherry and plum. In 2019–2020 surveys, 30 orchards in the apricot and almond production areas of Malatya and Elazıg provinces of Turkey exhibited blossom and twig blight symptoms. The objective of this study was to evaluate the in vitro and in vivo efficacy of boron products, pyroligneous acid and some fungicides on Monilinia laxa. Boron derivatives and boscalid were tested at different concentrations (0.01, 0.03, 0.05, 0.07, 0.09, 0.1,0.2, 0.4, 0.6%; w/v, μg.ml−1) for their inhibitory effect on mycelial growth of M. laxa. Mycelial growth of M. laxa was completely inhibited by boric acid (0.1%), borax (0.09%), Etidot (0.09%), pyroligneous acid (0.8%) and boscalid (0.6 µgml−1). Boric acid (0.12%), borax (0.1%), Etidot-67 (0.15%), PA (1.2%) and boscalid (0.8 µg ml−1) significantly inhibited germination of conidia of M. laxa isolates. EC50 values for 4 isolates of M. laxa ranged from 0.028 to 0.569% (MIC values ranged from 0.09 to 0.8 µgml−1) for mycelial growth and from 0.052 to 0.750% (MIC values ranged from 0.1 to 0.12) for conidial germination. In field trials conducted in the two subsequent years, boscalid + pyraclostrobin showed the highest efficacy (82.4% and 85.2%), followed by PA + borax (64.2% and 65.6%), PA + boric acid (48.2% and 54.6%), and boric acid + borax (18.2% and 21.9%, respectively). [ABSTRACT FROM AUTHOR]

Microbial resistance to drugs is a public health problem; therefore, there is a search for alternatives to replace conventional products with natural agents. One of the potential antimicrobial agents is wood vinegar derived from the carbonization of lignocellulosic raw materials. The objectives of the present work were to evaluate the antibacterial and antifungal action of two kinds of wood vinegar (WV), one of Eucalyptus urograndis wood and another of Bambusa vulgaris biomass, and determine their chemical profile. The antimicrobial effect was assessed against Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enteritidis, Escherichia coli, Streptococcus agalactiae, and Candida albicans. The minimum inhibitory concentration and the minimum bactericidal and fungicidal concentrations were determined. Micrographs of the microorganisms before and after exposure to both kinds of wood vinegar were obtained by scanning electron microscopy. The chemical profile of the eucalyptus and bamboo vinegar was carried out by gas chromatography and mass spectrometry (GC/MS). Both types of WV presented significant antimicrobial activity, with the bamboo one having a higher efficiency. Both studied pyroligneous extracts seem promising for developing natural antimicrobials due to their efficiency against pathogens. GC/MS analyses demonstrated that the chemical profiles of both kinds of WV were similar but with some significant differences. The major component of the eucalyptus vinegar was furfural (17.2%), while the bamboo WV was phenol (15.3%). Several compounds in both WVs have proven antimicrobial activity, such as acetic acid, furfural, phenol, cresols, guaiacol, and xylenols. Together, they are the major in the chemical composition of the organic fraction of both WVs. Bamboo vinegar had a more expressive content of organic acids. Micrographs of microorganisms taken after exposure to both kinds of wood vinegar displayed several cell modifications. The potential of both types of wood vinegar as a basis for natural antimicrobial products seems feasible due to their proven effect on inhibiting the microorganisms' growth assessed in this experiment. [ABSTRACT FROM AUTHOR]

The present study investigates the potential of biomass ash (BA) to produce nutrient-rich vermicompost for recycling within cropping systems. Initially, BA is thoroughly incorporated into dairy manure to obtain the final NPK content of 3.5 (T1), 7.0 (T2), 10.0% (T3) and control specifically is not exposed to BA (T0). The total readily available plant nutrient results indicated that vermicomposting significantly improved bioavailability of the investigated nutrients at the ranges of 0.5–95.6% (T1), 0.5–63.2% (T2), and 0.3–76.5% (T3), depending on the amount of BA in vermicompost. The present study also investigated the effect of BA vermicompost on the growth and yield of dry beans in two different agro-climatic conditions (hot dry summer and temperate regions). The significant increase in plants' height, pod numbers, dry biomass and grain yield are progressively observed with the increasing dose of BA in vermicompost at both agro-climatic conditions. The mean seed yield is higher in the temperate region (2819 kg ha−1) than in the hot dry summer climatic region (2616 kg ha−1). With this in mind, the increase of 13.80 and 12.99% in biomass and the seed yields are observed in the temperate region, while the biomass and seed yields are increased at 13.04 and 10.28% in the hot dry region due to the BA vermicompost application. The results show that the soil application of nutrient-rich BA vermicompost not only has a beneficial effect on crop production, but also provides viable alternative recycling options to BA in sustainable crop production systems. [ABSTRACT FROM AUTHOR]

Pyroligneous acid (PA) obtained from slow pyrolysis of palm kernel shell (PKS) has high total phenolic contents and exhibits various biological activities including antioxidant, antibacterial and antifungal. In this study, PA obtained using slow pyrolysis method and fractionated using column chromatography was characterized (chemical and antioxidative properties) and investigated for its cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) inhibition activities using the in vitro and in silico approaches. The F9 PA fraction exhibited highest total phenolic content of 181.75 ± 17.0 μg/mL. Fraction F21–25 showed ferric reducing antioxidant power (FRAP) (331.80 ± 4.60 mg TE/g) and IC50 of 18.56 ± 0.01 μg/mL towards COX-2 and 5.25 ± 0.03 μg/mL towards the 5-LOX enzymes, respectively. Molecular docking analysis suggested favourable binding energy for all chemical compounds present in fraction F21–25, notably 1-(2,4,6-trihydroxyphenyl)-2-pentanone, towards both COX-2 (− 6.9 kcal/mol) and 5-LOX (− 6.4 kcal/mol) enzymes. As a conclusion, PA from PKS has the potential to be used as an alternative antioxidant and antiinflammatory agents which is biodegradable and a more sustainable supply of raw materials. [ABSTRACT FROM AUTHOR]

Pyroligneous liquor and chitosan are natural and biodegradable products from renewable sources. Both present antimicrobial and antioxidant activities and induce resistance in plants, making these products promising to be used as raw material for agricultural inputs. Chitosan, dissolved in distilled pyroligneous liquor (DPL) from Eucalyptus grandis, produces colloidal systems with high ultraviolet absorption and it could be proposed as plant protective coating, based on their intrinsic characteristics. Chitosan undergoes degradation in an acidic environment; therefore, it is necessary to understand the stability of colloidal systems. We evaluated the systems obtained from chitosan and DPL for their physicochemical properties and structural characteristics at storage times at room temperature (20 ± 5 °C) up to 30 months. The colloidal systems presented a Newtonian flow during the storage time evaluated. Posteriorly, the colloidal systems were destabilized and the precipitates (PPT) were analyzed. Phenolic compounds from DPL were attached to the chitosan chains; this result is supported by fluorescence spectroscopy performed with PPT dissolved in non-fluorescent buffer. The PPT were fluorescent with emission maxima changing to higher wavelengths with storage time. The amounts of total phenols attached to polymer chains increased over time. As a result, there is an increase in the absorption of ultraviolet radiation with storage time. The results show that colloidal systems composed by chitosan formed complexes with phenolic compounds from DPL, which are promising for application in agriculture. [ABSTRACT FROM AUTHOR]

Huge volumes of lignocellulosic biomass residues generated from agricultural activities such as oil palm biomass pose great environmental threats if improperly treated. In this study, pyroligneous acid (PA) obtained from slow pyrolysis of palm kernel shell (PKS) were evaluated for its antioxidant activity via chemical assays, toxicity, and potential as anti-inflammatory agent based on nitric oxide (NO) inhibition activity. The PA was extracted using ethyl acetate (EA) and fractionated using column chromatography. Fractions 13–17 that contain highest total phenolic contents (866.84 ± 54.28 µg GAE/mg) were chosen for subsequent studies. Results obtained were as follows; DPPH—75.34 ± 3.40%, TEAC—1346.48 ± 5.29 μg Trolox/mg, FRAP—11.80 ± 0.41 mmol Fe(II)/mg, hydroxyl radical scavenging—IC50 270.34 ± 4.88 µg/mL, superoxide radical scavenging—IC50 472.32 ± 1.87 µg/mL, cytotoxicity after 24 h at less than 50 µg/mL—cell viability of ≥ 93.08% for RAW 264.7 macrophage cell and anti-inflammatory activity with NO production of 6.55% after 24 h at sample concentration of 25 µg/mL. From the GC–MS analysis, phenols and derivatives were identified as major compound (83.24%) followed by esters (11.23%), and ketones (5.53%). The present of phenolic compounds namely benzene-1,2-diol, catechol (35.01%), 1,3-dimethoxy-2-hydroxybenzene, syringol (23.81%), and other catechol derivatives can be attributed to the antioxidant and anti-inflammatory activities determined. This study has successfully demonstrated the potential use of PA obtained from PKS as alternative antioxidant and anti-inflammatory agent. [ABSTRACT FROM AUTHOR]

Physicochemical characteristics and in vitro antioxidant activities of four pyroligneous acids carbonized from the wastes of wood species including Mangosteen (Garcinia mangostana Linn.), Durian (Durio zibethinus L.), Rambutan (Nephelium lappaceum L.), and Langsat (Lansium domesticum Serr.) were assessed. Appearing as transparent liquors with pH 3.9–4.2, the pyroligneous acid samples under test possessed acetic acid (23.22–25.46%) as the dominant component. The total soluble tar, total acid, and water content were 0.15 − 0.28 wt%, 99–192 mg KOH/g and 84.5–93.5 wt%, respectively. Phenolic compounds namely: 2,6-dimethoxyphenol (6.88–9.69%), phenol (2.97–5.88%), 4-methylsyringol (3.10–3.56%), guaiacol (2.36–3.55%), and 2-methoxy-4-methylphenol (1.08–1.28%) were found. All had in vitro antioxidant activities especially mangosteen pyroligneous acid, which showed activity roughly similar to BHT (P > 0.05) against anti-lipid peroxidation. Nitric oxide scavenging capacities of all pyroligneous acids were significantly higher than BHT (P < 0.05). Our results suggest that pyroligneous acids from the four types of branch waste could be used as sources of beneficial natural antioxidants, possibly as food or feed additives to protect against lipid peroxidation, and potentially also in veterinary medicine in anti-inflammatory products. [ABSTRACT FROM AUTHOR]

Pyroligneous acid (PA) is a complex highly oxygenated aqueous liquid fraction obtained by the condensation of pyrolysis vapors, which result from the thermochemical breakdown or pyrolysis of plant biomass components such as cellulose, hemicellulose, and lignin. PA produced by the slow pyrolysis of plant biomass is a yellowish brown or dark brown liquid with acidic pH and usually comprises a complex mixture of guaiacols, catechols, syringols, phenols, vanillins, furans, pyrans, carboxaldehydes, hydroxyketones, sugars, alkyl aryl ethers, nitrogenated derivatives, alcohols, acetic acid, and other carboxylic acids. The phenolic components, namely guaiacol, alkyl guaiacols, syringol, and alkyl syringols, contribute to the smoky odor of PA. PA finds application in diverse areas, as antioxidant, antimicrobial, antiinflammatory, plant growth stimulator, coagulant for natural rubber, and termiticidal and pesticidal agent; is a source for valuable chemicals; and imparts a smoky flavor for food. [ABSTRACT FROM AUTHOR]

The limestone modified by pyroligneous acid has been proved to have good CO capture behavior in the calcium looping process. In this work, SO retention of the highly cycled modified limestone in the carbonation/calcination cycles was investigated in a thermogravimetric analyzer (TG). The cyclic carbonation/calcination of the modified limestone was performed in a dual fixed-bed reactor and then the cycled modified limestone was sent for sulfation in TG. The effects of sulfation temperature, cycle number, and prolonged carbonation on SO retention of the cycled modified limestone were discussed. The optimum temperature for sulfation of the cycled modified limestone should be in the range of 900-950 °C. The effect of sulfation temperature on SO retention of the modified limestone drops with increasing cycle number. With increasing cycle number from 20 to 100, the sulfation conversion of the cycled modified limestone is stable and can reach ~0.4. The cycled modified limestone exhibits obviously higher SO retention than the cycled raw one for the same number of cycles. The prolonged carbonation increases SO retention of the modified limestone and the raw one after the subsequent cycles. The sulfation conversions of the modified limestone and the raw one at 118 min after 9-h carbonation in the 20th cycle increase 43 and 56 %, respectively. The cycled modified limestone shows a greater SO retention than the cycled raw one after the same prolonged carbonation treatment. The prolonged carbonation increases the pores in 5-20 nm range which is considered the optimum pore size for sulfation of CaO-based sorbent, so it results in an improvement in SO retention of the cycled sorbents. [ABSTRACT FROM AUTHOR]