Revealing sulfate role in empowering the sulfur-oxidizing capacity of Thioalkalivibrio versutus D301 for an enhanced desulfurization process

Comprehensive insights into the gallic acid assisted bioleaching process for spent LIBs: Relationships among bacterial functional genes, Co(III) reduction and metal dissolution behavior

Despite the growing demand for resource recovery from spent lithium-ion batteries (LIBs) by bioleaching, low Co leaching efficiency has hindered the development and application of this technology. Therefore, a novel process was designed, combining gallic acid (GA) and mixed culture bioleaching (MCB), to enhance the removal of metals from spent LIBs. Results indicated that the GA + MCB process achieved 98.03% Co and 98.02% Li leaching from spent LIBs, simultaneously reducing the biotoxicity, phytotoxicity and leaching toxicity of spent LIBs under optimal conditions. The results of mechanism analysis demonstrated that functional microorganisms adapted to the leaching system through various strategies, including oxidative stress reduction, DNA damage repair, heavy metal resistance and biofilm formation, maintaining normal physiological activities and the continuous production of biological acid. The biological acid erodes the surface of waste LIBs, causing some Co and a large amount of Li to be released, while also increasing the contact area between GA and Co(III). Therefore, GA is beneficial for reducing insoluble Co(III), forming soluble Co(II). Finally, biological acid can effectively promote Co(II) leaching. Collectively, the results of this study provide valuable insight into the simultaneous enhancement of metal extraction and the mitigation of environmental pollution from spent LIBs.

Organic layer characteristics and microbial utilization of the biosulfur globules produced by haloalkaliphilic Thioalkalivibrio versutus D301 during biological desulfurization

The haloalkaliphilic genus Thioalkalivibrio, widely used in bio-desulfurization, can oxidize H₂S to S^o, which is excreted outside cells in the form of biosulfur globules. As by-product of bio-desulfurization, information on biosulfur globules is still very scant, which limits its high-value utilization. In this paper, the characteristics of biosulfur globules produced by Thioalkalivibrio versutus D301 and the possibility of cultivating sulfur-oxidizing bacteria as a high biological-activity sulfur source were studied. The sulfur element in the biosulfur globules existed in the form α-S₈, which was similar to chemical sulfur. The biosulfur globule was wrapped with an organic layer composed of polysaccharides and proteins. The composition of this organic layer could change. In the formation stage of biosulfur globules, the organic layer was dominated by polysaccharides, and in later stage, proteins became the main component. We speculated that the organic layer was mainly formed by the passive adsorption of organic matter secreted by cells. The existence of organic layer endowed biosulfur with better bioavailability. Compared with those found using chemical sulfur, the growth rates of Acidithiobacillus thiooxidans ATCC 19377^T, Thiomicrospira microaerophila BDL05 and Thioalkalibacter halophilus BDH06 using biosulfur increased several folds to an order of magnitude, indicating that biosulfur was a good sulfur source for cultivating sulfur-oxidizing bacteria.

College Organizational Innovation Performance-Oriented Internal Mechanism Analysis Using Lightweight Deep Learning under Health Psychology

The purpose is to improve employees’ initiative and innovation performance and further improve the overall organizational efficiency of colleges. From the perspective of health psychology, this work analyzes the internal mechanism between leadership empowerment behavior and employee innovation performance at China Agricultural University. By introducing two intermediate variables: task-based psychological capital (PsyCap) and innovative PsyCap, this work puts forward a lightweight deep learning (DL) model. It constructs the college organizational innovation performance (OIP)-oriented internal evaluation system from four dimensions. They are personal development support, power appointment, participation in decision-making, and work guidance. Then, the proposed lightweight DL model reveals the internal relationship between employees’ innovation performance and innovation factors using the questionnaire survey method. Overall, 360 questionnaires are distributed. The results show that the average values of the four dimensions (S, P, D, and G) of leadership empowerment are greater than 3, which are 4.3144, 4.3493, 4.4253, and 4.5286, respectively. S, P, D, and G represent empowerment, decision-making, communication, and innovation, respectively. The results show a high level of innovation performance in all dimensions. The finding proves that the influencing factors of employee innovation performance mainly include personal development support, empowerment, participation in decision-making, and work guidance. The effects of different dimensions vary significantly. Finally, the lightweight DL model can improve the analysis accuracy of the college OIP-oriented internal evaluation system. Therefore, college leaders should use the DL model and empowerment behavior to improve employees’ psychological quality, innovation enthusiasm, and work efficiency, ultimately benefiting employees.

Exploring the impact of biochar on antibiotics and antibiotics resistance genes in pig manure aerobic composting through untargeted metabolomics and metagenomics

This study investigated the effect of biochar on antibiotics and antibiotic resistance genes (ARGs) during aerobic composting of pig manure. First, the composition and content of antibiotics in the manure were determined qualitatively and quantitatively. Biochar promoted the degradation of these antibiotics (oxytetracycline, chlortetracycline, and tetracycline). The relative abundance (RA) of antibiotic-resistant bacteria carrying ARGs accounted for about 29.32% of the total bacteria. Firmicutes and Actinomycetes were dominant phylum-level bacteria at the early and late stages of composting, respectively. Biochar decreased the total RA of ARGs by 16.83%±4.10%. tetW and tetL, closely related to tetracycline resistance, were significantly diminished during aerobic composting, and biochar was able to promote this removal. Biochar enhanced RAs of Mycobacterium tuberculosis kasA mutant. RAs of ARGs related to antibiotic efflux pumps, such as baeS and arlS, remained at a high level. Conclusively, biochar promotes degradation of antibiotics and removal of ARGs.

Investigating role of abiotic side and finding optimum abiotic condition for improving gas biodesulfurization using Thioalkalivibrio versutus

Hydrogen sulfide (H₂S) is a super toxic substance that produces SO_x gases when combusted. Therefore, it should be removed from gas streams. Biodesulfurization is one of the developing methods for removing sulfide. Gas biodesulfurization must be accelerated to be competitive with chemical processes. This process has two sides: biotic and abiotic sides. To increase the rate of sulfide removal, this substance should be given to the bacteria in the maximum amount (Max. − R_{HS B}). Therefore, it is necessary to minimize the rate of adverse abiotic reactions of sulfide (Min. − R_{HS A}). Minimizing the sulfide reaction with biosulfur and oxygen and thiosulfate generation (Min. − R_{HS thio2}) was assessed in de-microbized medium. It was concluded that the pH should be kept as low as possible. The kinetics of thiosulfate formation from sulfide oxidation (− R_{HS thio1}) are strongly dependent on the sulfide concentration, and to minimize this reaction rate, sulfide should be gently injected into the culture. To minimize sulfide reduction to hydrogen sulfide (Min. − R_{HS rev}), the pH should be kept as high as possible. Using the Design Expert v.13, a model was driven for the abiotic side to obtain optimum condition. The pH value was found to be 8.2 and the sulfide concentration to 2.5E−05 M. Thioalkalivibrio versutus cultivation under identified abiotic conditions resulted in biological removal of sulfide up to 1.5 g/h. The culture was not able to remove 2 g/h input sulfide, and to increase this, the biotic side should be studied.