Screening Of The Mangrove Microbes Cytotoxic Active Substances In Wenchang

This thesis reported isolating and screening cytotoxic activity strains from mangrove, and strain 0616167 fermention condition optimization.The sample was collected from 18 kinds mangrove trees and 4 kinds semi-mangroves of soil, root, fruit and leef, totally 60 samples. 1206 strains were isolated, including 531 stains of bacteria, 384 stains of fungi and 291 strains of actinomycetes, of which 83, 77 and 66 strains were activie against B16 cell, respectively. Bacteria and fungi occupy the most of strong cytotoxic activity strains.Experiment results have been analyzed by SAS 6.12 statistic software. The results showed that different microorganism variety has remarkable relationship with their cytotoxic activity, among them, 29 strong cytotoxic activity strains were screened out from fungi, occupied 43.28% in total strong cytotoxic activity strains; Different sample collection part of mangrove trees has remarkable relationship with microorganism variety, among them, soil is the main source of actinomycetes, 244 strains were isolated, occupy 83.85% of total actinomycetes; Soil of Hibicus tilisaceus and Sonmratia alba has most abundant microorganism source, 9 and 5 of strong cytotoxic activite strains were found from their soil, respectively.Strain 0616167 was an actinomycete isolated from sea mud of mangrove in Wenchang city Hainan province. It has strong cytotoxic activity against B16 cell. Strain 0616167 grew well under 6% of salt. It's fermentation broth showed maximum activity at salt concentration between 0~3%, but decreased with salt concentration increase, until to no activity. Bioactivity of 0616167 was not affected by inoculation volume. Maximum activity showed in 10% (v/v) inoculation.Optimized fermention condition of strain 0616167 is that 20 g of glucose, 15 g of KNO3, as nitrogen source; 5 g of yeast extract; 2 g of peptone; 4 g of CaCO3; 4 g of NaCl; 1000mL of 50% sea water; pH 7.2-7.4; 75mL/250mL; fermentation time, 5 ds. The active substance is unstable under heat, the activity decreased while temperature increase. It maintained good stability under pH 5~11.