Effect of coexisting metal ions on bio-precipitation of Cu2+ phosphate by Rahnella sp. LRP3 and its stability in soil

The phosphate precipitation of heavy metal induced by microorganisms plays an important role in immobilising heavy metal in soil. However, there is little knowledge about the effect of coexisting metal ions on the induction of Cu phosphate mineral and its stability. In this paper, the Cu phosphate precipitations, coexisting with Pb²⁺ or Ca²⁺ induced by strain LRP3, were characterised, and the stabilisation of the induced phosphate precipitates was also studied. The coexistence of Cu with Pb or Ca decreased the removal efficiency of Cu²⁺ by 17.18% and 9.78%, respectively, indicating the competitive adsorption between cations. Strain LRP3 could induce a new phosphate mineral of CuCa₁₀(PO₄)₇ when coexisting with Ca and also generate the phosphate minerals of Pb(H₂PO₄)₂ and Cu₃(PO₄)₂ when coexisting with Pb. The Cu-Ca coprecipitate could enhance the stability of Cu in dilute acid solution and soil with or without a plant, whiles the Cu-Pb one showed the opposite effect. Also, the Cu-induced phosphate precipitates were relatively stable and not easy to be absorbed by Pakchoi (Brassica rapa var. chinensis). The results showed that the influence of coexisting metal ions should be considered when phosphate mineralisation technology is used to immobilise heavy metals in the environment.

Production of Bio-ethanol from Solid Waste Paper Using Biological Activation

Biomass energy is renewable energy source that comes from the material of plants and animals. Forms of biomass energy are bio-ethanol, bio methanol, and biodiesel. Bio-ethanol is one of the most important alternative energy sources that substitute the fossil fuels. The focus of this research is to produce bio-ethanol from waste office paper. Five laboratory experiments were conducted to produce bio-ethanol from wastepaper. The wastepaper was dried in oven and cut in to pieces. Then it passed through dilute acid hydrolysis, fermentation and distillation process respectively. High amount of ethanol was observed at 20 ml/g (liquid to solid ratio) and at the time of 2hr. Cost and economic analysis for ethanol production from wastepaper was performed. Results from the analysis indicated a paper to ethanol plant was feasible from the economic point of view with rate of return (RR) 38.61% and the payback period of 2.2 years.

The Kinetics Studies on Hydrolysis of Hemicellulose

The kinetics studies is of great importance for the understanding of the mechanism of hemicellulose pyrolysis and expanding the applications of hemicellulose. In the past years, rapid progress has been paid on the kinetics studies of hemicellulose hydrolysis. In this article, we first introduced the hydrolysis of hemicelluloses via various strategies such as autohydrolysis, dilute acid hydrolysis, catalytic hydrolysis, and enzymatic hydrolysis. Then, the history of kinetic models during hemicellulose hydrolysis was summarized. Special attention was paid to the oligosaccharides as intermediates or substrates, acid as catalyst, and thermogravimetric as analyzer method during the hemicellulose hydrolysis. Furthermore, the problems and suggestions of kinetic models during hemicellulose hydrolysis was provided. It expected that this article will favor the understanding of the mechanism of hemicellulose pyrolysis.

Polysaccharide Content and Growth Rate of Lessonia Variegata J. Agardh: Investigating its Potential as a Commercial Species

<p>The endemic brown alga Lessonia variegata has recently been shown to be four separate lineages. To determine differences between the four morphologically similar lineages, the economically valuable polysaccharides alginate and fucoidan were extracted and yields from each of the lineages were compared. In order to determine seasonal patterns in the yield of alginate and fucoidan, and the growth rate within L.variegata, polysaccharides were extracted and the growth rate measured on a monthly basis from March 2010 until February 2011 on plants from the Wellington lineage. The alginate and fucoidan yields were obtained via stepwise extraction with dilute acid and sodium carbonate as per the previously published methods of Usov et al. (1985). The growth rate of L. variegata from the Wellington lineage was assayed using the hole punch technique first described by Parke (1948). The yield of alginate within the Wellington lineage of L. variegata fluctuated seasonally with the highest percent occurring in spring and summer 2010. The yield of fucoidan in the Wellington lineage was at its highest in mid-autumn and late spring 2010. Two different growth rates were detected for the Wellington lineage of L. variegata. There was a period of significantly high growth from late winter 2010 until late summer 2011.The Wellington lineage had the lowest yield of alginate and the highest yield of fucoidan compared to the Northern lineage, the Kaikoura lineage and the Southern lineage. Based on the findings of this study, an appropriate harvest period for the Wellington lineage of L. variegata would be in early to mid-summer when polysaccharide yields and growth rates are high and the alga is vegetative.</p>