Metabolism of dibutyl-14C-labeled dibutylaminosulfenyl derivative of carbofuran in the cotton plant

The fate of the di-n-butylaminosulfenyl moiety in 2,3-dihydro-2,2-dimethyl-7-benzofuranyl (di-n-butylaminosulfenyl)(methyl)carbamate (DBSC or Marshal) was studied in the cotton plant at 1, 3, 6, and 10 days following foliage treatment with [di-n-butylamino-¹⁴C]DBSC. Dibutylamine and two major radioactive metabolites were obtained following extraction of the plant tissue with a methanol-buffer containing N-ethylmaleimide (NEM), a sulfhydryl scavenger which was added to prevent the cleavage of the NS bond during the workup procedure. The most adundant radioactive material recovered from plants was identified as a product arising from the reaction between NEM and dibutylamine. Extraction of plant tissue with straight methanol-buffer solution or with methol-buffer containing other sulfhydryl scavengers resulted in 57–86% of the applied radioactivity being recovered as dibutylamine in the organosoluble fraction. When [¹⁴C]dibutylamine was applied to cotton leaves, most of the radioactivity, i.e., 96% of the total recovered radioactivity, was found in the organosoluble fraction as dibutylamine. Dibutylamine is the major metabolite of [di-n-butylamino-¹⁴C]DBSC in the cotton plant.     

Synthesis and antifungal activity of imidazole-1-carboxylates

A series of imidazole-1-carboxylates was prepared by reacting various alcohols with trichloromethyl chloroformate and imidazole or N,N'-carbonyl-diimidazole. They were tested for fungitoxic activity in vitro against two phytopathogenic fungi, Botrytis cinerea (grey mould) and Gibberella fujikuroi, and for preventive efficacy against grey mould on cucumber leaves. 1-(4-Substituted phenoxymethyl)-2,2-dimethylpropylimidazole-1-carboxylates showed excellent in-vitro activity against B. cinerea, and moderate activity against G. fujikuroi, and some of them also effectively controlled grey mould in vivo. A 1H-1,2,4-triazole derivative corresponding to an imidazole derivative did not have any activity, while a thiocarboxylate corresponding to an imidazole carboxylate showed excellent activity against both B. cinerea and G. fujikuroi.     

Methane production from thermophilic co‐digestion of dairy manure and waste milk obtained from therapeutically treated cows

Methane production from co‐digestion of dairy manure and waste milk, milk from cows treated with antibiotics for mastitis, was tested in a 2 × 4 factorial design. Four different waste milk percentages (w/w): 0% (SM), 10% (SMWM10), 20% (SMWM20) and 30% (SMWM30), were tested with two slurry percentages (w/w): 50% (A) and 25% (B) and the rest being manure at 55°C for 12 days in batch digesters. The results analyzed using a Gompertz model showed SMWM10 produced the highest methane production potential (P_m)/g volatile solids added followed by SM in both A and B. This P_m of SMWM10 in A and B was statistically non‐significant (P > 0.05). More than 96% of cefazolin‐resistant bacteria and 100% of multi‐drug‐resistant bacteria reductions were observed in all the treatments. Inclusion of waste milk at 10% in single stage digester enhances the methane production from dairy manure and could offer added benefit of waste milk treatment and disposal.     

Effect of substituting soybean meal with euglena (Euglena gracilis) on methane emission and nitrogen efficiency in sheep

This study evaluated methane (CH₄) emission, intake, digestibility, and nitrogen efficiency in sheep fed diets containing replacement levels (0%, 33%, 50%, and 67% of soybean meal with euglena). In this experiment, four Corriedale wether sheep with an initial body weight of 53.8 ± 4.6 were arranged in a 4 × 4 Latin square design. This experiment lasted 84 days, divided into four experimental periods. Each period lasted 21 days, which consists of 14 days of adaptation to the diets, 5 days to collect samples, and 2 days to collect gas emission from sheep. Methane emission expressed as L/kg DM intake or g/kg DM intake reduced by up to 37% and the energy loss via CH₄ (% of GE intake) reduced by up to 34%. No differences (p > 0.05) were observed in DM and OM intake and whole tract apparent DM digestibility due to substitution of soybean meal with euglena. The total CP loss reduced significantly (linear, p < 0.001) and CP efficiency increased linearly (p = 0.03) with increasing concentration of euglena. As a result, nitrogen balance and average daily weight gain remained unchanged despite higher nitrogen concentration in soybean supplemented group. In conclusion, substitution of soybean meal with euglena reduced methane emission without affecting the performance of animals.     

Metabolism of 2,3-dihydro-2,2-dimethyl-7-benzofuranyl (di-n-butylaminosulfenyl)(methyl)carbamate and 2,3-dihydro-2,2-dimethyl-7-benzofuranyl (morpholinosulfenyl)(methyl)carbamate in cotton and corn plants

The absorption, translocation, and metabolism of two new, selectively toxic derivatives of carbofuran, 2,3-dihydro-2,2-dimethyl-7-benzofuranyl (di-n-butylaminosulfenyl)(methyl)carbamate and 2,3-dihydro-2,2-dimethyl-7-benzofuranyl (morpholinosulfenyl)(methyl)carbamate, were studied in cotton and corn plants 1, 3, 6, and 10 days following both stem injection and foliage treatment. Both carbamates were readily translocated to all plant parts following stem injection, but translocation following leaf application was restricted to within the leaf. In cotton plants, the dibutylaminosulfenyl derivative was easily hydrolyzed to form carbofuran which, in turn, was oxidized at the 3-position of the ring and the N-methyl group. These oxidized metabolites were then converted to plant conjugates. Major metabolites were carbofuran and 3-hydroxy-carbofuran followed by 3-keto-carbofuran phenol and N-hydroxymethyl-carbofuran. Five minor metabolites also were detected. In corn plants, the dibutylaminosulfenyl derivative gave the same metabolites, although the metabolism rate was significantly slower in corn relative to cotton. Overall, the results showed that there were no fundamental differences in the metabolism of the morpholinosulfenyl and dibutylaminosulfenyl derivatives. The stability of both carbamate derivatives in different solvent systems also was investigated.     

The survival of pathogenic bacteria and plant growth promoting bacteria during mesophilic anaerobic digestion in full‐scale biogas plants

The introduction of biogas plants is a promising way to recycle organic wastes with renewable energy production and reducing greenhouse gas. Application of anaerobic digestate as a fertilizer reduces the consumption of chemical fertilizers. In this study, the survival of pathogenic bacteria and plant growth promoting bacteria (PGPB) in two full‐scale biogas plants operated at mesophilic condition were investigated. Feedstock and anaerobic digestate samples were collected from biogas plants and bacteria load in samples were detected using standard dilution plate method. Pathogenic bacteria were reduced to not detected level through mesophilic digestion tank except for Campylobacter. However, it could be reduced by 98.7% through a sterilization tank. Bacillus was detected at 8.00 and 7.81 log₁₀ CFU/g dry matter in anaerobic digestates, and it was also resistant to sterilization tank. Bacillus spp. is considered to be the safe bacteria that hold remarkable abilities for promoting plant growth. The results showed that treatment at biogas plants is effective to reduce pathogenic bacteria in dairy manure, and sterilization could further reduce the sanitary risks of pathogenic bacteria relating to anaerobic digestate application. Anaerobic digestates could also be utilized as bio‐fertilizer as the high load of plant growth promoting bacteria.     

Anaerobic co-digestion of dairy manure and Japanese knotweed (Fallopia japonica) under thermophilic condition: Optimal ratio for biochemical methane production

Anaerobic co-digestion of animal manure and lignocellulosic biomass is a potent approach for sustainable biomethane production. Co-digestion of dairy manure (DM) and Japanese knotweed (JK), which was collected from a riverbank, was investigated at five different DM-to-JK mixing ratios (100:0, 90:10, 80:20, 60:40, and 0:100; wet weight basis) under thermophilic condition. The results showed that the methane yields obtain from the co-digestion of DM and JK were much higher than that obtained from JK alone (104 ml/gVS), which indicates the synergistic effect and the benefits of co-digesting JK with DM. The highest methane yield (232 ml/gVS) was obtained from the DM-to-JK ratio of 90:10, which was 14.9% and 123.1% higher than that from DM and JK alone, respectively. It also showed the highest synergistic effect (61 ml/gVS). However, further increase in JK ratios led to the decrease in methane yield and synergistic effect. Therefore, applying the co-digestion of DM and JK at a ratio of 90:10 is recommended for biomethane production.     

The survival of multidrug‐resistant bacteria in thermophilic and mesophilic anaerobic co‐digestion of dairy manure and waste milk

Anaerobic digestion is considered as a promising method to manage animal waste with antibiotic‐resistant bacteria. Current research was conducted to investigate the survival of multidrug‐resistant bacteria (MDRB) resistant to three groups of antibiotics: (i) cefazolin, neomycin, vancomycin, kanamycin (group 1); (ii) penicillin, oxytetracycline, ampicillin, streptomycin (group 2); and (iii) cefazolin, neomycin, vancomycin, kanamycin, penicillin, oxytetracycline, ampicillin, streptomycin (group 3), in anaerobic digestion of dairy manure and co‐digestion of dairy manure and waste milk at 37°C and 55°C for 22 days, respectively. The population densities of three groups of MDRB on peptone, tryptone, yeast and glucose agar plates incubated at 30°C for 7 days before and after digestion showed 100% destruction in both digestates at thermophilic temperature. Overall reduction of more than 90% of three groups of MDRB was observed in mesophilic digestion with no significant differences (P > 0.05) between manure and milk mixture. Co‐digestion of dairy manure and waste milk always produced significantly (P < 0.05) higher total gas and methane gas than digestion of manure alone at both temperatures. Gas production in each case was significantly (P < 0.05) higher in thermophilic digestion than in mesophilic digestion. The results demonstrate that thermophilic co‐digestion of dairy manure and waste milk offers more benefits in terms of the environment and economy.