RESUMO
The nicotine from tobacco stalk showed obvious inhibitory effect on the activity of cellulase and fermentability of microorganisms, which seriously hinders the utilization of tobacco stalk. Dilute sulfuric acid presoak of tobacco stalk was used to enhance the performance of instant catapult steam explosion (ICSE) for tobacco stalk pretreatment. The presoak was beneficial to break the recalcitrant structure of tobacco stalk, reduce nicotine content to relieve the inhibition on the activity of cellulase and metabolism of microorganisms, and promote the performance of enzymatic hydrolysis and ethanol fermentation. The optimized 0.8% sulfuric acid (w/w) presoak-integrated ICSE pretreatment resulted in 85.54% nicotine removal from tobacco stalk; meanwhile, the total sugar concentration from enzymatic hydrolysis of pretreated tobacco stalk increased from 33.40 to 53.81 g/L (the ratio of dry tobacco stalk to water was 1:8, w/w), ethanol concentration increased 103.36% from 5.95 to 12.10 g/L in flask, compared with separate ICSE pretreatment. Finally, the ethanol concentration achieved the highest 23.53 g/L in a 5-L fermenter with the ethanol yield from the glucose of tobacco stalk hydrolysate achieving 71.40% by increasing the solid loading of the tobacco stalk in the enzymatic hydrolysis process (the ratio of dry tobacco stalk to water was 1:4, w/w). These results achieved the expected purpose of efficient utilization of discarded tobacco stalk.
RESUMO
As a natural plant source of artemisinin,a first-line drug against malaria,Artemisia annua directly affects the extraction process of artemisinin and the source of artemisinin. At present,traditional breeding methods combined with tissue culture are often used to breed high-yield artemisinin-containing new varieties of A. annua. However,the breeding method has the disadvantages of low efficiency and continuous selection. In this study,heavy ion beam irradiation technology was used to observe the specific germplasm resources of A. annua,and the morphological characteristics,agronomic traits and artemisinin content were used as indicators to observe the selection materials and materials. The cultivated new varieties were compared with trials and regional trials. In addition,the new variety of A. annua was identified by SRAP molecular marker technology. The results showed that the new variety of A. annua, " Kehao No.1",had an average yield of 235. 0 kg of dry leaf per mu,which was more than 20% higher than that of the control. Especially,the average artemisinin content was 2. 0%,which was 45% higher than that of the control,and the " Kehao No.1" has high anti-white powder disease,high-yield and high-quality new varieties. Therefore,mutagenic breeding of heavy ion beam irradiation can significantly improve the yield and artemisinin content of the " Kehao No. 1" and it has a good promotion value.
