Lipase and photodecarboxylase coexpression: A potential strategy for alkane-based biodiesel production from natural triglycerides

Alkane-based biodiesel is considered the next generation of biodiesel owing to its potential environmental benefits and the fact that it exhibits much higher specific caloric values than traditional biodiesel.However,the formidable obstacle impeding the commercialization of this cutting-edge fuel alternative lies in the cost associated with its production.In this study,an engineered strain Escherichia coli(E.coli)showcasing harmonized coexpression of a lipase(from Thermomyces lanuginosus lipase,TLL)and a fatty acid photodecarboxylase(from Chlorella variabilis,CvFAP)was first constructed to transform triglycerides into alkanes.The potential of E.coli BL21(DE3)/pRSFDuet-1-TLL-CvFAP for alkane synthesis was evaluated with tripalmitin as a model substrate under various process conditions.Following a comprehensive examination of the reaction parameters,the scope of the biotransformation was expanded to‘real’substrates(vegetable oils).The results showed that bioderived oils can be transformed into alkanes with high yields(0.80-10.20 mmol·L^(-1))under mild conditions(35℃,pH 8.0,and 36 h)and blue light illumination.The selected processes were performed on an increased lab scale(up to 100 ml)with up to 24.77 mmol·L^(-1) tripalmitin,leading to a yield of 18.89 mmol·L^(-1) pentadecane.With the employment of a method for efficiently producing alkanes under mild conditions and a simple procedure to isolate alkanes from the reaction system,the utilization of sustainable biomass as a fundamental feedstock emerges as the primary solution to lower the cost of alkane-based biodiesel.Thus,this study proposes a readily implementable and highly effective approach for alkane-based biodiesel production.

Novel model combining contrast-enhanced ultrasound with serology predicts hepatocellular carcinoma recurrence after hepatectomy

BACKGROUND Surgery is the primary curative option in patients with hepatocellular carcinoma(HCC).However,recurrence within 2 years is observed in 30%–50%of patients,being a major cause of mortality.AIM To construct and verify a non-invasive prediction model combining contrastenhanced ultrasound(CEUS)with serology biomarkers to predict the early recurrence of HCC.METHODS Records of 744 consecutive patients undergoing first-line curative surgery for HCC in one institution from 2016–2018 were reviewed,and 292 local patients were selected for analysis.General characteristics including gender and age,CEUS liver imaging reporting and data system(LIRADS)parameters including wash-in time,wash-in type,wash-out time,and wash-out type,and serology biomarkers including alanine aminotransferase,aspartate aminotransferase,platelets,and alpha-fetoprotein(AFP)were collected.Univariate analysis and multivariate Cox proportional hazards regression model were used to evaluate the independent prognostic factors for tumor recurrence.Then a nomogram called CEUS model was constructed.The CEUS model was then used to predict recurrence at 6 mo,12 mo,and 24 mo,the cut-off value was calculate by X-tile,and each C-index was calculated.Then Kaplan-Meier curve was compared by logrank test.The calibration curves of each time were depicted.RESULTS A nomogram predicting early recurrence(ER),named CEUS model,was formulated based on the results of the multivariate Cox regression analysis.This nomogram incorporated tumor diameter,preoperative AFP level,and LIRADS,and the hazard ratio was 1.123(95%confidence interval[CI]:1.041-1.211),1.547(95%CI:1.245-1.922),and 1.428(95%CI:1.059-1.925),respectively.The cut-off value at 6 mo,12 mo,and 24 mo was 100,80,and 50,and the C-index was 0.748(95%CI:0.683-0.813),0.762(95%CI:0.704-0.820),and 0.762(95%CI:0.706-0.819),respectively.The model showed satisfactory results,and the calibration at 6 mo was desirable;however,the calibration at 12 and 24 mo should be improved.CONCLUSION The CEUS model enables the well-calibrated individualized prediction of ER before surgery and may represent a novel tool for biomarker research and individual counseling.

Diagnosis and Treatment of Cholangiocarcinoma: A Consensus from Surgical Specialists of China

Cholangiocarcinoma refers to malignant tumors that develop in epithelial lining of biliary system, and it is divided into two categories according to tumor location, intrahepatic cholangiocarcinoma （ICC） and extrahepatic cholangiocarcinoma （ECC）. ICC occurs from the epithelial cells of the intrahepatic bile duct, its branches and interlobular biliary tree; and ECC is divided into hilar cholangiocarcinoma and distal cholangiocarcinoma by the circumscription at the confluence of cystic duct and the common hepatic duct.