The study is the development of biological methods for extracting gold from the effluents of the gold processing and gold extraction in the industries where has a very high acidity (pH 0-4). This method should be used to replace the electrochemical process and chemical method which cause the pollution of toxic substances acid fumes and heavy metals of copper cyanide to the environments. The research started at the characterization and identification of microorganisms presented in gold contaminated water in natural source where is highly acidic (pH 2-4) and it could synthesize nanogold particles. The bacteria Bacillus sp. E201 were identified from this source and it showed its 16S rDNA gene with similarity of 95% to bacteria Bacillus thuringiensis accession no. FJ755916. It could create gold in the solution outside the cells within three days Form 1 mM HAuCl4 • 3H2O solution the bacterial dry weight could yield 75.3% with the amount of 0.5115 grams. It could be able to withstand acidic conditions and harvest gold from the gold extraction solution after centrifugation and filtration. So this developed biological method could be developed to apply in the industrial production of gold and jewelry industry.

Moisture content has a marked influence on all aspects of paddy and rice quality. These issues also have significantly importance for rice industry and economy of Thailand. Many drying process such as spouted bed technique and fluidized bed technique are extremely studied in terms of instrument design and energy consumption. However these drying processes were not suitable for high economic rice. Because of these processes performed highly damaged kernels during drying process. The objective of this project we proposed the alternative drying system that perform low damaged paddy kernels. We also were design and fabrication drying system for paddy in terms of conveyer pipe. This machine have the performance including feed rate approximately 22.83 kg/hr. drying temperature 30-120ºC air velocity 0-1.5 m/s drying time 14.64-16.91 min and energy consumption 6.02 baht/hr. We improved our machine by drying the RD41 paddy at moisture content 28 (%w.b.). We also setup drying temperatures 40°C 45°C 50°C 55°C and 60°C with air velocities 0.7m/s 1.0m/s and 1.5m/s. We found that all drying temperatures have the final moisture content lower than 15 (%w.b.) and percentage of complete paddy after drying (HRY-paddy) more than 96%. For the kernels quality we found that HRY-Brown rice tend to increase with drying temperature increased. We also found that HRY-Unbroken kernels for polishing tend to decrease between drying temperature 40°C - 50°C for air velocities 0.7m/s and 1.5m/s. Therefore these results obtained can be such a high potential approach that can be used for further developing into rice economy and industry of Thailand.