Glycolic acid-based deep eutectic solvents boosting co-production of xylo-oligomers and fermentable sugars from corncob and the related kinetic mechanism.

BACKGROUND: Xylo-oligomers are a kind of high value-added products in biomass fractionation. Although there are several chemical methods to obtain xylo-oligomers from biomass, the reports about the deep eutectic solvents (DESs)-mediated co-production of xylo-oligomers and fermentable sugars and the related kinetic mechanism are limited. RESULTS: In this work, glycolic acid-based DESs were used to obtain xylo-oligomers from corncob. The highest xylo-oligomers yield of 65.9% was achieved at 120 °C for 20 min, of which the functional xylo-oligosaccharides (XOSs, DP 2-5) accounted for up to 31.8%. Meanwhile, the enzymatic digestion of cellulose and xylan in residues reached 81.0% and 95.5%, respectively. Moreover, the addition of metal inorganic salts significantly accelerated the hydrolysis of xylan and even the degradation of xylo-oligomers in DES, thus resulting in higher selectivity of xylan removal. AlCl3 showed the strongest synergistic effect with DES on accelerating the processes, while FeCl2 is best one for xylo-oligomers accumulation, affording the highest xylo-oligomers yield of 66.1% for only 10 min. Furthermore, the kinetic study indicates that the 'potential hydrolysis degree' model could well describe the xylan hydrolysis processes and glycolic acid/lactic acid (3:1) is a promising solvent for xylo-oligomers production, in particular, it worked well with FeCl2 for the excellent accumulation of xylo-oligomers. CONCLUSIONS: Glycolic acid-based deep eutectic solvents can be successfully applied in corncob fractionation with excellent xylo-oligomers and fermentable sugars yields on mild conditions, and the large amount of xylo-oligosaccharides accumulation could be achieved by specific process controlling. The strategies established here can be useful for developing high-valued products from biomass.

Primary adenocarcinoma of the bladder lacks mismatch repair deficiency and demonstrates PD-L1 expression in tumor-infiltrating immune cells, with implications in both diagnosis and therapeutics.

Primary adenocarcinoma of the bladder is a rare and highly aggressive disease with no standard therapy. Effectiveness of immune checkpoint blockade in bladder adenocarcinoma is unknown due to lack of clinical trials. Due to the disease rarity, the rate of PD-L1 expression and DNA mismatch repair deficiency is largely unknown. In this study, we examined PD-L1 expression in 56 cases of bladder adenocarcinoma and mismatch repair protein expression in 42 cases of bladder adenocarcinoma using immunohistochemistry. Mismatch repair protein expression was uniformly intact in all cases of bladder adenocarcinoma, in comparison with 19% of advanced colorectal adenocarcinoma being mismatch repair deficient. This finding indicates that mismatch repair proteins may be combined with ß-catenin and GATA-3 to create an immunostaining panel which, in addition to clinical studies, can aid in distinguishing bladder adenocarcinoma from secondary involvement by colorectal carcinoma. 4% of cases were found to overexpress PD-L1 in tumor cells while approximately a third of cases were found to display PD-L1 expression in tumor-infiltrating immune cells. These results indicate hypermutators are likely rare in bladder adenocarcinoma, yet 20-30% of the patients may be eligible for immune checkpoint blockade therapy.