No abstract

Human living environments and health are seriously affected by the odor produced from fermentation of livestock and poultry manure. In order to reduce the odor pollution caused by livestock and poultry manure, efficient strains were screened and two methods were tried in this study. The orthogonal test design was used to analyze the gas produced by pig manure under different conditions of temperature, time, wheat straw doping amount and calcium carbonate doping amount. Then, according to ammonia, hydrogen sulfide and comprehensive odor removal effects, the high efficiency of deodorizing strains were screened. The results showed that pig manure produced the least odor when the temperature was 20 °C, added 0% calcium carbonate, 20% wheat straw and waited for 48 h. Three strains were screened to inhibit the odor production of pig manure: Paracoccus denitrificans, Bacillus licheniformis and Saccharomyces cerevisiae, showed that their highest removal rate of ammonia and hydrogen sulfide gas could reach 96.58% and 99.74% among them; while for three strains of end-control pig manure stench: Pichia kudriavzevii, P. denitrificans and Bacillus subtilis, the highest removal rate of ammonia and hydrogen sulfide gas reached 85.91% and 90.80% among them. This research provides bacteria resources as the high-efficiency deodorizing function for the source suppression and the end treatment of the odor gas of pig manure, which has high application value for the control of odor pollution.

Polylactic acid has good biodegradability and it is dosage is increasing. Therefore, the degradation of PLA has become a new problem that needs serious management. In this study, the spores of Aspergillus niger were inoculated onto wheat straw/PLA composites containing different contents of sodium alginate, and the mass loss and characterization (microstructure, fourier transform infrared spectroscopy, thermal properties, and X‐ray diffraction) of the composites were detected. The objective was to explore the possibility of degradation of PLA composites by A. niger and the effect of sodium alginate on the degradability of PLA composites. The results showed that when the amount of sodium alginate was 3% and 6%, the mass loss rate of the composites only increased at the initial stage of degradation. However, when the amount of sodium alginate was 9%, the mass loss rate of the composites was significantly increased. It was found that A. niger could colonize the surface of the composites and cause cracks and depressions on the surface by morphological observation. The infrared spectral curve showed that the number of hydroxyl and carbonyl groups in the composites increased after degradation. According to the thermogravimetric curve of the composites, the pyrolysis temperature of the composites with sodium alginate content of 9% increased and the residual mass decreased after degradation. When the amount of sodium alginate was 9%, the crystallinity of the composites was greatly reduced, and it is crystallization zone was easier to degrade compared with other treatments. The results would provide a theoretical support for the rapid degradation of PLA composites.

Fusarium graminearum is the main pathogen of Fusarium head blight (FHB), which causes huge economic losses every year. In this study, an attempt was made to control FHB from the point of view of the physiological behavior of the pathogen itself. Autophagic inhibitors and activators were used, and the pathogenicity-related indices of F. graminearum were measured. The results showed that under nitrogen-rich conditions, macroautophagy inhibition and activation greatly reduced the mycelium weight to 0.28 and 0.25 g/mL at 24 h, which were 17.82% and 24.77% lower than that of the control treatment, respectively. Mitophagy inhibition also significantly decreased the mycelium weight (P<0.05). Conidial yield was found to be affected by factors related to autophagy occurrence. It was found that both autophagy inhibition and activation could reduce the conidiation of F. graminearum. The toxin contents in wheat medium of macroautophagy activation treatments were 0.678, 0.190, 0.402 and 0.195 μg/g when cultured for 8 and 24 h under 0% N and 100% N conditions, respectively, which were significantly higher than those of the control treatments (P<0.05). The infection length was measured to characterize the infectivity of F. graminearum, and we found that the length was short under macroautophagy activation conditions. However, mitophagy did not seem to affect the infectivity of F. graminearum. In summary, the above results indicated that macroautophagy and mitophagy inhibition could reduce the pathogenicity of F. graminearum, which would provide a new perspective for management of plant fungal diseases.

In order to improve the degradability of polylactic acid (PLA) composites and screen PLA degradation microorganisms. Sodium alginate was added into the wheat straw/PLA composites, and both composites (with/without sodium alginate) were buried in natural soil for 100 consecutive days subsequently.Weight loss and characterization of the PLA composites, carbon and nitrogen content in soil and microbial community composition were detected after degradation, with the result that the degradability of the PLA composites was greatly improved after the addition of sodium alginate. The weight loss of PLA composites with sodium alginate was 8.5%, which was 1.81 times that of PLA composites without sodium alginate. Sodium alginate and/or wheat straw in the PLA composites took the lead in the beginning course of the degradation. The added sodium alginate serves the purpose of making it easier to degrade the crystallization zone of the PLA composites. Bionectriaceae in the soil shoots up in the number after degradation, signifying its potential to be part of the microorganism family serving to degrade PLA composites. The results would help reveal the degradation mechanism of PLA composites and provide support for the screening of PLA composites degradation microorganisms.