Abstract: A protoplast fusion was conducted between two efficient photosynthetic bacteria,N-ammonia degrading Candida sp.and N-nitrite degrading Rhodospeudomonas capsulate.The conditions of the protoplast formation and fusion were optimized,and the best fusant was selected.The better protoplast formation for Rhodospeudomonas capsulata was found under the conditions of:lysozyme at 1.5 mg/mL,EDTA 0.1 g/L and 45 min reaction time;for Candida sp.the better conditions of snail enzyme at 0.5 mg/mL,mercaptoethanol 0.1%,EDTA 1 g/L and 30 min reaction time.The fusion was induced by PEG 6000 and Ca2+.Fusants were screened out by selective media containing added nystatin and streptomycin.The fusant R1 with better efficient degradation was selected by growth stability and degradation.The fusant R1 showed N-nitrite degradation at a rate of more than 90%,as good as for Rhodospeudomonas capsulata,but had N-ammonia degradation of only 63%,increased by 54%.
2011, Vol. 26 
