A Citrus Peel Waste Biorefinery for Ethanol and Methane Production

Abstract

This paper deals with the development of a citrus peel waste (CPW) biorefinery that employs low environmental impact technologies for production of ethanol and methane. Three major yeasts were compared for ethanol production in batch fermentations using CPW pretreated through acid hydrolysis and a combination of acid and enzyme hydrolysis. The most efficient conditions for production of CPW-based hydrolyzates included processing at 116 °C for 10 min. Pichia kudriavzevii KVMP10 achieved the highest ethanol production that reached 30.7 g L−1 in fermentations conducted at elevated temperatures (42 °C). A zero-waste biorefinery was introduced by using solid biorefinery residues in repeated batch anaerobic digestion fermentations achieving methane formation of 342 mL gVS−1 (volatile solids). Methane production applying untreated and dried CPW reached a similar level (339–356 mL gVS−1) to the use of the side stream, demonstrating that the developed bioprocess constitutes an advanced alternative to energy intensive methods for biofuel production.

Preliminary Study on Biethanol Production from Starchy Foodwastes by Immobilized Saccharomyces cerevisiae

“…Temperature also can affect the enzymatic activity and turgidity of yeast cells membrane greatly. It was reported that the performance of S. cerevisiae in bioethanol production is reduced at temperatures higher than 37 o C [31]. This result is in accordance with the study of Vohra et al [32] in which the fermentation temperature for food waste for bioethanol production is in the range of 30-37 o C. This is because the microorganism will becomes more active when warm and dies at high temperature.…”

Power and Limitations of Biochemical Methane Potential (BMP) Tests

“…In this mode of operation, any potential toxicant does not reach steady-state levels in the mixed liquor over time. While continuous experiments are one option to study chronic toxicity, repeated re-feeding of the assay once the stable plateau phase of the methane production is reached is another one (Patsalou et al, 2019). Also, due to the short test duration, BMP tests cannot assess the capability of the anaerobic microbial community to adapt to the inhibitor over time (Astals et al, 2015).…”

Direct Construction of K-Fe3C@C Nanohybrids Utilizing Waste Biomass of Pomelo Peel as High-Performance Fischer–Tropsch Catalysts

“…S7: Fe 2p orbital XPS data of Fe@C-1.0 and spent Fe@C-1.0. [11,26,50,[54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69].…”