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Pyroligneous acid (PA) is a by-product of bio-oil, which is obtained by pyrolysis of the wood. This product has been tested for use in several areas, such as agriculture, as a promising green herbicide; however, there are few scientific data regarding its environmental impacts. For this study, an ecotoxicity testing battery, composed of Daphnia magna acute toxicity test, Allium cepa test and in vitro Comet assay with the rainbow trout gonad-2 cell fish line (RTG-2) were used to evaluate the acute toxicity and genotoxicity of PA obtained from fast pyrolysis of eucalyptus wood fines. The PA presented acute toxicity to D. magna (microcrustacea) with EC 50 of 26.12 mg/L, and inhibited the seed germination (EC 50 5.556 g/L) and root development (EC 50 3.436 g/L) of A. cepa (higher plant). No signs of genotoxicity (chromosomal aberrations and micronuclei in A. cepa and primary DNA lesions in RTG-2 cells) were detected to this product. The acute toxicity and absence of genotoxicity may relate to the molecules found in the PA, being the phenolic fraction the key chemical candidate responsible for the toxicity observed. In addition, daphnids seem to be more sensitivity to the toxicity of PA than higher plants based on their EC 50 values. This first ecotoxicological evaluation of PA from fast pyrolysis pointed out the need of determining environmental exposure limits to promote the safer agriculture use of this product, avoiding impacts to living organisms. • Pyroligneous acid produced by fast pyrolysis without PAH's components. • Main components obtained by GC-MS were anhydrosugar and hydroxybenzenes. • Concentration used as herbicide is potentially toxic for D. magna , EC50 26.12 mg/L. • Considered moderately phytotoxic for A. cepa without damaging the genetic material. • No significant genotoxic effects using Comet assay with the fish cell line RTG-2. [ABSTRACT FROM AUTHOR]

To identify the major mutagen in pyroligneous acid (PA), 10 wood and 10 bamboo pyroligneous acids were examined using the Ames test inSalmonella typhimuriumstrains TA100 and TA98. Subsequently, the mutagenic dicarbonyl compounds (DCs), glyoxal, methylglyoxal (MG), and diacetyl in PA were quantified using high-performance liquid chromatography, and the mutagenic contribution ratios for each DC were calculated relative to the mutagenicity of PA. Eighteen samples were positive for mutagens and showed the strongest mutagenicity in TA100 in the absence of S9 mix. MG had the highest mutagenic contribution ratio, and its presence was strongly correlated with the specific mutagenicity of PA. These data indicate that MG is the major mutagen in PA. Pyroligneous acids showed the mutagenicity by the Ames test, and methylglyoxal was identified as a major mutagen. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assign the utilization of Asper Backer bamboo charcoal as activated carbon and pyroligneous acid as an alternative coagulating and antifungal agents for natural rubber sheet production. The effect of chemical activation process of bamboo charcoal was investigated. The physical properties like iodine number, moisture, ash, volatile and fixed carbon contents were measured. The results were found that the bamboo activated carbon has the highest iodine number value of 1398 mg/g which indicating a large of adsorption capacity at the optimum conditions as microwave power of 360 watts, activation time of 15 mins and the ratio of charcoal: phosphoric acid as 1: 4. In addition, the effect of coagulating and anti-fungal activities of pyroligneous acid that is a by-product of Dendrocalamus Asper Backer bamboo charcoal burning was also observed. The comparison properties of pyroligneous acid with the commercial wood vinegar, formic and acetic acids have been measured. The coagulating efficiency of pyroligneous acid exhibited the shortest possible coagulation time at 18.30 mins between acids and latex. Herein, the antifungal efficiency was determined from a fungi growth area only 5% on air dried sheet rubber surfaces. The results were found that the coagulating and anti-fungal properties showed in the following order of commercial wood vinegar > bamboo pyroligneous acid > formic acid > acetic acid according to their acidic and phenolic compound contents. [ABSTRACT FROM AUTHOR]

Urea is one of the most commonly used nitrogen fertilizers in agricultural soil and is easily decomposed by soil urease resulting in ammonium release. The produced ammonium can be volatilized or converted to nitrate, which is susceptible to leaching, leading to groundwater contamination unless used by plants. Hence, it is important to control the release of nitrogen from the urea. Pyroligneous acid inhibited the urease activity and decreased ammonium release up to 80% compared to the control. Amidase including asparaginase and glutaminase is an enzyme that catalyzes hydrolysis of amide group, similar to urease. Therefore, the effect of pyroligneous acid on the inhibition of soil amidase was also tested and the results showed that pyroligneous acid competitively inhibited asparaginase while glutaminase was not inhibited. However, inhibitory effect of pyroligneous acid on asparaginase was negligible compared to the urease. The application of pyroligneous acid with a smaller amount of urea for controlled nitrogen release during Chinese cabbage growth showed that dry biomass and nutrient contents of Chinese cabbage were similar to the case of the conventional urea application. The nitrogen utilization efficiency (NUE) was highest for 33% less amount of urea supply with pyroligneous acid (2.21) compared to conventional treatment (1.81). Consequently, the use of pyroligneous acid with urea enhances nitrogen use efficiency while also protecting environments from non-point source contamination. • Pyroligneous acid inhibited urease activity in soil. • Pyroligneous acid competitively inhibited soil asparaginase while not inhibiting glutaminase. • Pyroligneous acid enhanced nitrogen use efficiency of Chinese cabbage. • Controlled nitrogen release reduces the likelihood of environmental pollution. Pyroligneous acid enhanced nitrogen use efficiency of Chinese cabbage by controlling release of ammonium from urea, which acted as an effective urease inhibitor. [ABSTRACT FROM AUTHOR]

Both biochar (BC) and wood vinegar (WV) influence the nitrous oxide (N 2 O) and methane (CH 4) emissions from agricultural systems. However, the impacts of BC and WV co-application on rice production, N 2 O and CH 4 emissions are not well documented. We here conducted a two-year soil columns experiment with four treatments: WV (5 t WV ha−1), BC (7.5 t BC ha−1), WV + BC (5 t WV ha−1 +7.5 t BC ha−1) and a control (no treatment). The results showed that BC and WV + BC produced higher rice grain yield than the control by 14.1–15.9% in 2016 and by 4.1–5.2% in 2017, respectively. While WV increased rice grain yield by 11.2% in 2016, it had no significant influence on yield in 2017. Both WV and BC significantly mitigated N 2 O emissions by 22.4–41.8% in 2016 and 22.4–36.9% in 2017, respectively. Interestingly, WV + BC treatment showed the highest N 2 O mitigation efficiency, with a 52.9–62.8% mitigations in 2016 and 2017. Furthermore, the co-application of WV and BC significantly mitigated CH 4 emissions by 42.6% in 2016 and 35.3% in 2017, respectively, while applying WV or BC alone had no annually-consistent mitigation effect on CH 4 emissions. Overall, GWPt of rice growth cycle was most significantly suppressed by WV + BC with a 48.7–56.1% reduction, followed by WV and BC with 20.4–28.0% and 19.7–35.7% reductions, respectively. Consequently, the WV + BC treatment had the highest GHGI mitigation effect, averaging with 56.7% over two consecutive rice growth cycles. In conclusion, co-application of WV and BC is recommended for rice cultivation, which can both improve rice yield and minimize GHG emissions. Image 1 • Effects of alone- and co-application of BC and WV on GHG emissions were studied in a two-year study. • BC and WV co-application functioned highest N 2 O and CH 4 mitigation efficiency. • Co-application of BC and WV mitigated GHGI by averaged 56.7% in two rice growth cycles. [ABSTRACT FROM AUTHOR]

Cyanobacteria blooms are crucial environmental issues by threatening both aquatic ecosystem and human health. A biomass by-product with antimicrobial activity, pyroligneous acid (PA) was tested for its suitability for removal of the cyanobacteria Microcystis aeruginosa (M. aeruginosa) in this work. Results show that the removal efficiency could reach up to 90% in the presence of 0.45% of PA and the inhibition to M. aeruginosa growth could extend to at least 40 days. The removal mechanism was studied. Both organic acids and phenols are functional content in M. aeruginosa removal and acetic acid is the most important one. Zeta potential analysis and morphology study show that the damage of cells dominates the flocculation and sedimentation of M. aeruginosa under low PA concentration (<0.7%), and increasing PA (≥0.7%) resulted in a trend of zeta potential to zero, thus removing any "shield" and triggering flocculation. Finally, study on the phenols residual after M. aeruginosa treatment shows that it could be close to 0 in 70 h. Therefore, this work proposes a possible method for world-wide treatment of cyanobacteria bloom and a new way for further utilization of PA. • Pyroligneous acid has been developed for Microcystis aeruginosa removal here. • Removal mechanism depends on the concentration of pyroligneous acid. • Phenols residual after Microcystis aeruginosa treatment are close to 0 in 70 h. [ABSTRACT FROM AUTHOR]

Botrytis cinerea can cause grey mould and seriously affect the commercial value of grapes. An artificial inoculation trial was done using table grape 'Red Globe' (Vitis vinifera L.). Grape berries were treated either with ultrapure water or 600, 400, 200 times dilution of wood vinegar (WV), followed by inoculation with B. cinerea suspension after 24 h. Disease incidence (DI), disease severity (DS), malondialdehyde (MDA) and hydrogen peroxide content and activities of peroxidase, ascorbate peroxidase, superoxide dismutase, polyphenol oxidase, chitinase, and β-1,3-glucanase were determined every two days during B. cinerea infection. Compared with the positive control group, WV treatment significantly reduced the DI and DS of grapes infected with grey mould. WV significantly decreased the amount of hydrogen peroxide and MDA and promoted the accumulation and expression of antioxidant enzyme in grapes. These results suggested the efficacy of WV treatment in improving the resistance of 'Red Globe' grapes to grey mould and in mitigating harm caused by oxidative stress. [ABSTRACT FROM AUTHOR]