Arsenic bioleaching in medical realgar ore and arsenicbearing refractory gold ore by combination of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans

Purpose: To develop a novel biotechnological method for removing toxic arsenic from two kinds of representative arsenic-containing ores using different mixed mesophilic acidophiles.Methods: Bioleaching of the two types of arsenic-containing ores by mixed arsenic-unadapted Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans or mixed arsenic-adapted cultures, were carried out. Arsenic bioleaching ratios in the various leachates were determined and compared.Results: The results showed that the maximum arsenic leaching ratio obtained from realgar in the presence of mixed adapted cultures was 28.6 %. However, the maximum arsenic leaching ratio from realgar in the presence of mixed unadapted strains was only 12.4 %. Besides, maximum arsenic leaching ratios from arsenic-bearing refractory gold ore by mixed adapted strains or unadapted strains were 45.0 and 22.9 %, respectively. Oxidation of these two ores by sulfuric acid was insignificant, as maximum arsenic leaching ratios of realgar and arsenic-bearing refractory gold ore in the absence of any bacterium were only 2.8 and 11.2 %, respectively.Conclusion: Arsenic leaching ratio of realgar and refractory gold ore can be enhanced significantly in the presence of arsenic-adapted mesophilic acidophiles.Keywords: Adaptation, Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, Realgar, Arsenicbearing refractory gold ore, Arsenic leaching rati

Changes of Key Soil Factors, Biochemistry and Bacterial Species Composition during Seasons in the Rhizosphere and Roots of <i>Codonopsis pilosula</i> (tangshen)

Codonopsis pilosula is a medicinal and edible herb with a rich nutritional value. In Gansu Province, China, its production quality and yield differ during the four seasons. Here, we investigated the differences in the microfloral composition and metabolic functions in the rhizospheric soil and roots of C. pilosula during the four seasons, and we also analyzed their dynamic and synergistic effects on C. pilosula growth and carbohydrate content change. The C. pilosula samples were analyzed for plant physiology, microfloral composition and metabolic functions in the rhizospheric soil and roots using high-throughput sequencing technology. Environmental indices including soil physiochemistry and meteorological conditions were also determined by the coupled chromatography–spectroscopy technique. The results revealed that the C. pilosula growth was affected by temperature, precipitation and light intensity, with the bacterial structures and functions of the soil and root samples showing obvious seasonal changes. Due to the diversity of microbial composition and community metabolic function, and the synergistic effect of microbial and environmental factors, there are significant differences in stress resistance, physiological status and metabolites of C. pilosula in different seasons. Furthermore, the change in seasons was significantly correlated with the quality and yield of C. pilosula. This study provides a scientific basis for soil improvement and the refinement of local Radix C. pilosula cultivation methods

Comparative Production Performance and Rumen Bacterial Diversity of Fattening Beef Cattle Supplemented with Different Levels Concentrated Feed

The production performance and rumen bacterial diversity were compared for different silage-based diets supplemented with common concentrate or bio-concentrate to develop an alternative of common concentrate for fatten cattle feeding. The daily gain of fattening cattle was increased by 0. 99 kg and 1.04 kg, respectively, when fed with single corn silage or mixed silage-based diet supplemented with bio-concentrate. There was no significant difference in water loss rate and cooked meat rate among groups (P>0.05), but the tenderness of beef in the bio-concentrate group was significantly higher than that in the common concentrate group (P<0.05). There were no adverse effects on beef quality and blood biochemical indexes in each group. Compared with the normal concentrate group, the OTU number and α-diversity index of rumen microorganisms of fattening cattle fed with mixed silage as the basic diet supplemented with bio-concentrate increased significantly. At generic level, the relative abundances of Prevotella, Porphyromonadaceae (unclassified), and Succiniclasticum were increased by adding bio-concentrate in the diets based on mixed silage and single sorghum silage. Relative abundances of Bacteroidetes (unclassified), Ruminococcaceae (unclassified), and Firmicutes (unclassified) decreased. In conclusion, the bio-concentrate might be a better choice than common concentrate for beef cattle breeding

Insights into the Structures, Inhibitors, and Improvement Strategies of Glucose Oxidase

Glucose oxidase, which uses molecular oxygen as an electron acceptor to specifically catalyze the conversion of &beta;-d-glucose to gluconic acid and hydrogen peroxide (H2O2), has been considered an important enzyme in increasing environmental sustainability and food security. However, achieving the high yield, low price and high activity required for commercial viability remains challenging. In this review, we first present a brief introduction, looking at the sources, characteristics, catalytic process, and applications of glucose oxidase. Then, the predictive structures of glucose oxidase from two different sources are comparatively discussed. We summarize the inhibitors of glucose oxidase. Finally, we highlight how the production of glucose oxidase can be improved by optimizing the culture conditions and microbial metabolic engineering

Culturable endophytic fungi community structure isolated from Codonopsis pilosula roots and effect of season and geographic location on their structures

Abstract Background Rhizosphere soil physicochemical, endophytic fungi have an important role in plant growth. A large number of endophytic fungi play an indispensable role in promoting plant growth and development, and they can provide protection for host plants by producing a variety of secondary metabolites to resist and inhibit plant pathogens. Due to the terrain of Gansu province is north–south and longitudinal, different climatic conditions, altitude, terrain and growth environment will affect the growth of Codonopsis pilosula, and the changes in these environmental factors directly affect the quality and yield of C. pilosula in different production areas. However, In C. pilosula, the connection between soil nutrients, spatiotemporal variation and the community structure of endophytic fungi isolated from C. pilosula roots has not been well studied. Results Seven hundred six strains of endophytic fungi were obtained using tissue isolation and the hyphaend-purification method from C. pilosula roots that picked at all seasons and six districts (Huichuan, HC; Longxi, LX; Zhangxian, ZX; Minxian, MX; Weiyuan, WY; and Lintao, LT) in Gansu Province, China. Fusarium sp. (205 strains, 29.04%), Aspergillus sp. (196 strains, 27.76%), Alternaria sp. (73 strains, 10.34%), Penicillium sp. (58 strains, 8.22%) and Plectosphaerella sp. (56 strains, 7.93%) were the dominant genus. The species composition differed from temporal and spatial distribution (Autumn and Winter were higher than Spring and Summer, MX and LT had the highest similarity, HC and LT had the lowest). physical and chemical of soil like Electroconductibility (EC), Total nitrogen (TN), Catalase (CAT), Urease (URE) and Sucrase (SUC) had significant effects on agronomic traits of C. pilosula (P < 0.05). AK (Spring and Summer), TN (Autumn) and altitude (Winter) are the main driving factors for the change of endophytic fungal community. Moreover, geographic location (such as altitude, latitude and longitude) also has effects on the diversity of endophytic fungi. Conclusions These results suggested that soil nutrients and enzyme, seasonal variation and geographical locations have an impact on shaping the community structure of culturable endophytic fungi in the roots of C. pilosula and its root traits. This suggests that climatic conditions may play a driving role in the growth and development of C. pilosula