A waste biomass based hydrogel soybean residue-poly(acrylic acid) (SR-pAA) was prepared through a fast one-step reaction by UV radiation technology. SR-pAA was used to remove cd(ii) and pb(ii) ions from aqueous solutions. Effect of pH value, temperature, initial concentration, contact time, competitive ions in the solutions on metal ions adsorption and desorption/regeneration capacity of SR-PAA was discussed in detailed. It was found that the adsorption equilibrium was achieved within 20 min, and maximum adsorption for Cd(II) and Pb(II) ions were 1.43 and 2.04 mmol g −1 , respectively. Besides, adsorption thermodynamic analysis indicates that the process of cd(ii) and pb(ii) ions adsorption was spontaneous, feasible and exothermic in nature. And experimental data fitted the pseudo-second-order and freundlich isotherm model well. Moreover, XpS spectra analysis proves that the metal ions were adsorbed on SR-pAA due to the interaction of carboxyl, hydroxyl and amine with these ions as ionic bond, coordination bond and electrostatic interaction. Increasing industrialization has brought great challenges to the environment. Like China, many countries face more and more enormous environmental problems, especially water pollution caused by heavy metal ions 1-3. Among various heavy metals, Cd(II) and Pb(II) have strong toxicity, which can damage to animals and human bodies seriously though the food chain. The report from United States Environmental Protection Agency showed that cadmium can cause respiratory cancers, for example, lung carcinoma 4 , and lead can cause cognitive dysfunction in children, hypertension, immune system and reproductive system diseases 5. Consequently, it is particularly necessary to remove the heavy metal ions from the wastewater before discharge it into the environment. Adsorption is a common method to remove various heavy metal ions from the wastewater. Many kinds of adsorbents, including activated carbon 6 , inorganic minerals 7 , biomass adsorbents 8-10 , and polymer 11-14 , are used to remove the metal ions from the wastewater. Metal ions adsorption capability of an adsorbent is mainly controlled by the surface active sites (functional groups such as carboxyl, hydroxyl, amino and hydrosulphonyl) of the adsorbent 15. The metal ions that contact with the adsorbent surfaces may be attached to the surfaces of the adsorbent according to physical or chemical interaction. Then those metal ions can be adsorbed on the adsorbent by ion exchange, coordination interaction, electrostatic interaction and physical adsorption, which are considered to be the main mechanism of most adsorbents to remove metal ions. In particular, it has been reported that the group of carboxyl, hydroxyl and amino are extremely advantageous to the metal ions removal from various aqueous solutions 6,9,16-19. Hence, many researchers are interested in the functional groups modified adsorbents to enhance the capability of metal ions removal. However, an efficient, low-cost, easily obtained and environmental friendly adsorbent is ve...

Cigar tobacco leaves (CTLs) contain abundant bacteria and fungi that are vital to leaf quality during fermentation. In this study, artificial fermentation was used for the fermentation of CTLs since it was more controllable and efficient than natural aging. The bacterial and fungal community structure and composition in unfermented and fermented CTLs were determined to understand the effects of microbes on the characteristics of CTLs during artificial fermentation. The relationship between the chemical contents and alterations in the microbial composition was evaluated, and the functions of bacteria and fungi in fermented CTLs were predicted to determine the possible metabolic pathways. After artificial fermentation, the bacterial and fungal community structure significantly changed in CTLs. The total nitrate and nicotine contents were most readily affected by the bacterial and fungal communities, respectively. FAPROTAX software predictions of the bacterial community revealed increases in functions related to compound transformation after fermentation. FUNGuild predictions of the fungal community revealed an increase in the content of saprotrophic fungi after fermentation. These data provide information regarding the artificial fermentation mechanism of CTLs and will inform safety and quality improvements.

Many microorganisms, growing on aging flue-cured tobacco leaves, play a part in its fermentation process. These microflora were identified and described by culture-dependent methods earlier. In this study we report the identity of the microflora growing on the tobacco leaf surface by employing culture-independent methods. We have amplified microbial 16S rDNA sequences directly from the leaf surface and used denaturing gradient gel electrophoresis (DGGE) to identify bacterial community on the tobacco leaves. Our culture-independent methods for the study of microbial community on tobacco leaves showed that microbial community structures on leaves of variety Zhongyan 100, NC89 and Zhongyan 101 were similar between 0 and 6 months aging, and between 9 and 12 months aging, while the similarity is low between 0 and 6, and between 9 and 12 months aging, respectively. There were certain similarities of bacterial communities (similarity up to 63%) among the three tobacco varieties for 0 to 6 months aging. Five dominant 16S rDNA DGGE bands A, B, C, D and E were isolated, cloned, and sequenced. They were most similar to two cultured microbial species Bacteriovorax sp. EPC3, Bacillus megaterium, and three uncultured microbial species, respectively.

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