Xylitol Production by Candida tropicalis from Areca Nut Husk Enzymatic Hydrolysate and Crystallization

d-Xylitol Production from Sugar Beet Press Pulp Hydrolysate with Engineered Aspergillus niger

d-Xylitol is a low-calorie and anti-cariogenic sweetener suitable for diabetic patients, making it a valuable ingredient in various health-related applications. In this study, we investigated the production of d-xylitol from l-arabinose derived from sugar beet press pulp (SBPP) hydrolysate using an engineered Aspergillus niger strain. Initial batch studies applying stirred tank bioreactors demonstrated d-xylitol production of 4.6 g L-1 with a yield of 0.37 g d-xylitol g-1 l-arabinose with a synthetic medium. Subsequently, the conversion of enzymatically produced and clarified SBPP hydrolysate was studied. We found that pre-treatment of the enzymatic hydrolysate with activated carbon was essential to remove inhibitory components. Moreover, an automated aeration switch-off was implemented based on the CO2 signal of the off-gas analyzer of the stirred tank bioreactor to prevent d-xylitol degradation after l-arabinose depletion. This resulted in a final d-xylitol concentration of 4.3 g L-1 with an improved yield of 0.43 g d-xylitol g-1 l-arabinose. The feasibility of utilizing the agricultural residue SBPP for d-xylitol production was successfully demonstrated with engineered A. niger.

Development of a novel direct compressible co-processed excipient and its application for formulation of Mirtazapine orally disintegrating tablets

INTRODUCTION

Orally disintegrating tablets (ODTs) are designed to dissolve in the oral cavity within 3 min, providing a convenient option for patients as they can be taken without water. Direct compression is the most common method used for ODTs formulations. However, the availability of single composite excipients with desirable characteristics such as good compressibility, fast disintegration, and a good mouthfeel suitable for direct compression is limited.

OBJECTIVE

This research was proposed to develop a co-processed excipient composed of xylitol, mannitol, and microcrystalline cellulose for the formulation of ODTs.

METHODS

A total of 11 formulations of co-processed excipients with different ratios of ingredients were prepared, which were then compressed into ODTs, and their characteristics were thoroughly examined. The primary focus was on evaluating the disintegration time and hardness of the tablets, as these factors are important in ensuring the ODTs meet the desired criteria. The model drug, Mirtazapine was then incorporated into the chosen optimized formulation.

RESULTS

The results showed that the formulation comprised of 10% xylitol, 10% mannitol and 80% microcrystalline cellulose demonstrated the fastest disintegration time (1.77 ± 0.119 min) and sufficient hardness (3.521 ± 0.143 kg) compared to the other formulations. Furthermore, the drug was uniformly distributed within the tablets and fully released within 15 min.

CONCLUSION

Therefore, the developed co-processed excipients show great potential in enhancing the functionalities of ODTs, offering a promising solution to improve the overall performance and usability of ODTs in various therapeutic applications.

Physicochemical Pretreatment of Vietnamosasa pusilla for Bioethanol and Xylitol Production

The consumption of fossil fuels has resulted in severe environmental consequences, including greenhouse gas emissions and climate change. Therefore, transitioning to alternative energy sources, such as cellulosic ethanol, is a promising strategy for reducing environmental impacts and promoting sustainable low-carbon energy. Vietnamosasa pusilla, an invasive weed, has been recognized as a high potential feedstock for sugar-based biorefineries due to its high total carbohydrate content, including glucan (48.1 ± 0.3%) and xylan (19.2 ± 0.4%). This study aimed to examine the impact of NaOH pretreatment-assisted autoclaving on V. pusilla feedstock. The V. pusilla enzymatic hydrolysate was used as a substrate for bioethanol and xylitol synthesis. After treating the feedstock with varying concentrations of NaOH at different temperatures, the glucose and xylose recovery yields were substantially higher than those of the untreated material. The hydrolysate generated by enzymatic hydrolysis was fermented into bioethanol using Saccharomyces cerevisiae TISTR 5339. The liquid byproduct of ethanol production was utilized by Candida tropicalis TISTR 5171 to generate xylitol. The results of this study indicate that the six- and five-carbon sugars of V. pusilla biomass have great potential for the production of two value-added products (bioethanol and xylitol).