Pu Xiang,Qu Xixing,Chen Fei,Bao Jinku,Zhang Guolin,Luo Yinggang
Camptothecin (CPT), the third largest anticancer drug, is produced mainly by Camptotheca acuminata and Nothapodytes foetida . CPT itself is the starting material for clinical CPT-type drugs, but the plant-derived CPT cannot support the heavy demand from the global market. Research efforts have been made to identify novel sources for CPT. In this study, three CPT-producing endophytic fungi, Aspergillus sp. LY341, Aspergillus sp. LY355, and Trichoderma atroviride LY357, were isolated and identified from C. acuminata . Most CPT produced by these fungi was found in the fermentation broth, and their corresponding CPT yields were 7.93, 42.92, and 197.82 μg l −1 , respectively. The CPT-producing capability of LY341 and LY355 was completely lost after repeat subculturing. A substantial decrease of CPT production was also observed in the second generation of LY357. However, a stable and sustainable production of CPT was found from the second generation through the eighth generation of LY357. The fermentation medium, time, pH, temperature, and agitation rate were optimized for CPT production. Methyl jasmonate and XAD16 were proven to be an optimum elicitor and adsorbent resin, respectively, in view of that CPT yield was increased 3.4- and 11-fold through their use. A 50- to 75-fold increase of CPT yield was obtained when the optimized fermentation conditions, elicitor, and adsorbent resin were combined and applied to the culture of the seventh and eighth generations of LY357, and the highest CPT yield was 142.15 μg l −1 . The CPT-producing T. atroviride LY357 paves a potential to uncover the mysteries of CPT biosynthesis.
Excessive use of organophosphate pesticides (OP), such as dichlorvos, in farming system poses a threat to human health through potential contamination of environment. To date, biodegradation has been prospected most promising approach to eliminate environmental OP residues. Trichoderma species as a biological control microorganism is often exposed to the chemical pesticides applied in environments, so it is necessary to understand the mechanism of degradation of dichlorvos by Trichoderma . In this study, dichlorvos significantly inhibited the growth, sporulation and pigmentation of T. atroviride T23, and the dichlorvos degradation activity of T23 required the initial induction effect of dichlorvos and the culture conditions, including the nutrient and pH values of the medium. Various changed primary and secondary metabolites released from T23 in the presence of dichlorvos were speculated as the energy and antioxidants for the strain itself to tolerate dichlorvos stress. The results showed that T23 could produce a series of enzymes, especially the intracellular enzymes, to degrade dichlorvos. The activities of the intracellular enzyme generated by T23 were differentially changed along time course and especially relied on initial dichlorvos concentration, ammonium sulfate and phosphate added in the medium. In conclusion, some dichlorvos-induced chemical degradation related enzymes of T23 were proved to be involved in the degradation of dichlorvos.
危险品化学品经营许可证（带存储）