Production, Purification and Decolorization of Microbial Levan Using Fallen-Leaves Extract Medium; 낙엽추출물 배지를 이용한 미생물 레반의 생산, 정제 및 탈색

초록

Fallen leaves are often viewed as nuisance unused forest biomass, contributing to wildfire risks and sewer blockages. However, they also present a valuable resource for producing high-value-added products. In a previous study, we demonstrated the economic feasibility of cultivating Pseudomonas species microorganisms using a hardwood fallen leaf extract (HLE)-based medium. This study focuses on further utilization of the HLE medium to produce levan, a functional natural polymer, by addition of sucrose as a carbon source and cultivation of Pseudomonas chlororaphis. Over a 72-hour cultivation, the cell growth-dependent levan production was monitored, resulting in a yield of 7.1 g/L from 19.6 g/L of sucrose (36.7% conversion yield). The crude levan was purified through a straightforward filtration process. However, the purified levan exhibited a dark-brown color due to the inherent pigmentation of the HLE, which could limit its industrial applications. To address this, we conducted decolorization experiments using eight different materials, with activated charcoal designed for water treatment showing the highest efficacy. Under the optimal decolorization conditions, the produced levan achieved a clear, colorless appearance. Taken together, this study confirms the industrial feasibility of using fallen leaf-based media for the production of high-value bioproducts like levan. © 2024 Korean Technical Assoc. of the Pulp and Paper Industry. All rights reserved.

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