Current World Environment

The efficient bioconversion of lignocellulosic biomass into xylitol is often hindered by the presence of inhibitory phenolic compounds released during pretreatment and hydrolysis. However, the presence of inhibitory compounds in wheat straw hydrolysate (WSH) limits its direct utilization during microbial fermentation. The present study aimed to evaluate the effectiveness of treatment strategies for improving the quality of WSH while preserving sugars. A technique for reducing phenolic compounds from WSH was developed and optimized by assessing the influence of different alkaline agents (NaOH, Ca(OH)2, and NH3) in combination with activated charcoal treatment. Major process variables, including pH, incubation time, temperature, and fixed concentration of activated charcoal application, were systematically investigated to enhance the clarification efficiency of WSH for thereafter microbial processing. Among the tested bases, NaOH treatment achieved the highest phenolic removal efficiency, followed by Ca(OH)2, and NH3. Optimization of pH revealed that pH 10 resulted in the maximum phenolic reduction of74.1% with minimal sugar loss. Temperature optimization indicated that treatment at 30 °C was effective, achieving 76.6% phenolic removal and the highest sugar retention. The incubation time significantly influenced detoxification efficiency, where 12 h showed optimal phenolic removal 77.8% while preserving total sugars (12.8%, w/v and reducing sugars (10.9%, w/v).The removal of inhibitory process resulted in a substantial reduction in phenolic content, improvement in hydrolysate clarity, and enhanced recovery of reducing sugars. These improvements indicate that the treated hydrolysate is more suitable for subsequent microbial fermentation processes. Overall, the study demonstrates that the combined alkaline treatment, process variable optimization, and activated charcoal detoxification approach effectively reduced the phenolic content and enhanced the suitability of WSH, supporting its use as a substrate for downstream xylitol fermentation.

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