TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Method: In (M1), the hydrolysis process is performed on the conditions of heating and pressurizing the plant that absorbed heavy metal in sulfuric acid. The sugar content in the hydrolysis processed liquid is converted into alcohol using alcohol fermentation microorganisms. EXAMPLE - Recovery of arsenic from Morinda citrifolia and ethanol production was carried out as follows. M.citrifolia was collected from the domestic mountainous area. A Wagnor pot was filled with 200 g (arsenic content of 600 gm/l) of arsenic-containing andisol as dry soil, and 42 ml of culture medium of the international rice research institute (IRRI) was added as a fertilizer, to produce the test soil. A plant was transplanted to the test soil and was allowed to grow for 120 days. After 120 days, the plant was crushed (50 nm or less) and was further crushed (6 mm or less). The content of arsenic in the crushed material was measured, and was found to contain 5000 mg/kg (per dry weight) of arsenic. Then, the crushed material was dipped in 1% sulfuric acid, at was processed at pressure of 5-6 kg/cm2 and temperature of 150-160degreesC for 10 minutes, and the pentose component was extracted. Slake lime was added to the solution and the solution was neutralized. After neutralization, the solution was added to a primary fermenter, ethanol fermentation microorganism was added, and ethanol fermentation was performed. The plant residue in the solution was recovered, and dipped in 2% sulfuric acid, and was processed at a temperature of 200degreesC and pressure of 20 mg/cm2 for 1 minute, and hexose component was extracted. Lime was added to the solution and was neutralized. After neutralization, the solution was added to a secondary fermenter, and budding yeast (Saccharomyces cerevisiae, IF02347) was added, and ethanol fermentation was performed. Alcohol was recovered from the primary and secondary fermenter. Then, when the distillation dehydration was performed, 2.7 L ethanol was recovered. The waste liquid after recovering the alcohol from the primary and secondary fermenter was concentrated. The arsenic concentration in the concentrated solution was 12857 ppm. The waste liquid after concentrating was mixed with sodium hypochlorite and ferric chloride, and was stirred for 30 minutes. The arsenic concentration in the waste liquid was 0.1 ppm. The results showed that 99% or more of arsenics contained in the M.citrifolia was efficiently recovered, and ethanol was recovered by the 0.13 l/kg ratio from the carbohydrate fraction except 25% of lignin components contained in biomass.