[Objective] The Cu-tolerance and Cu enrichment capacity of TLSB2-K were investigated. [Method] The previously isolated TLSB2-K strain was identified though morphological observation, gram staining and 16S rDNA sequence alignment. In ad- dition, the effects of temperature, pH and osmotic pressure on the growth of strain were also investigated by using shaking culture. The Cu-tolerance and Cu enrich- ment capacity of TLSB2-K strain under Cu stress were also studied. [Result] The results showed TLSB2-K belongs to Bacillus spp., and its optimum growth conditions were as follows： temperature, 27 ~C; pH, 7.0; osmotic pressure, 1.1% NaCI. When the Cu concentration ranged from 100 mg/L to 500 mg/L, the strain grew well; when the Cu concentration ranged from 100 mg/L to 400 mg/L, the Cu content in bacteria was increased with the increase of Cu concentration; when the Cu con- centration was 400 mg/L and the incubation time was 30 h, the Cu content in bac- teria reached the peak （2 250 mg/kg）; the highest tolerant concentration was 700 mg/L. [Conclusion] TLSB2-K strain had relatively high Cu tolerance and Cu enrich- ment capacity. They had important theoretical research and engineering application values.
Ricinus communis L. is a new copper hyperaccumulator growing on Tonglushan copper mine in Hubei Province, China. This study aimed to establish a suspension cell line of R. communis L. with stable and rapid growth for further screening of heavy metal-resistant R. communis L. cells and breeding of hyperaccu- mulators. In this study, cell suspension culture conditions were optimized by using orthogonal experimental design with previously induced R. communis L. embyre- genic calluses as experimental materials, to establish the suspension cell line of R. communis L. Under the optimal conditions, growth curves of suspension cells and changes in pH of culture liquid were determined. The results showed that the optimal culture conditions for R. conmmnis L. suspension cell line were ： MS ＋ O. 5 rag/I, 6-BA ＋ O. 2 mg/L NAA ＋ 50 mg/L sucrose ＋ 350 mg/L casein hydrolysate as basic medium, with callus inoculation amount of 2.5 g/50 ml, dark culture at （26 ±2） ℃ with shaking at 110 r/min. Under these conditions, increment of fresh weight and dry weight ofR. commun/s L. suspension cells reached the maximum of 4.56 g/（50 ml 14 d） and 0.49 g/（50 ml 16 d）, respectively. Growth curves of R. communis L. suspension cells were basically in ＂S＂ shape. Each culture cycle lasted 16 d, and the rapid growth stage was from the 6th d to the 14th d. In a culture cycle, pH of the culture liquid declined first and then increased to the maximum and stabilized gradually.
