Controlling bacterial contamination during fuel ethanol fermentation using thermochemically depolymerized lignin bio-oils
| Autor: | Sue E. Nokes, Ryan M. Kalinoski, Wenqi Li, Bert C. Lynn, Jian Shi, Xiaowen Chen, Justin K. Mobley |
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| Rok vydání: | 2021 |
| Předmět: |
010405 organic chemistry
fungi food and beverages 02 engineering and technology Ethanol fermentation 021001 nanoscience & nanotechnology Biorefinery 01 natural sciences Pollution Yeast 0104 chemical sciences Lactic acid chemistry.chemical_compound Corn stover chemistry Peracetic acid Environmental Chemistry Lignin Fermentation Food science 0210 nano-technology |
| Zdroj: | Green Chemistry. 23:6477-6489 |
| ISSN: | 1463-9270 1463-9262 |
| DOI: | 10.1039/d1gc01521d |
| Popis: | Lactic acid bacteria (LAB) contamination during fuel ethanol fermentation can lead to significant economic loses. To circumvent this, fuel ethanol plants add antibiotics prophylactically, but their overuse has resulted in the emergence of antibiotic-resistant LAB strains. Lignin is a sustainable biopolymer that can be found as a waste product from lignocellulosic biorefineries. Technical lignins and their smaller phenolic subunits have been shown to exhibit broad-spectrum antimicrobial properties, but there is a lack of demonstrations of lignin derivatives with highly selective properties in the literature. Here, corn stover lignin from a biorefinery was oxidatively depolymerized using an environmentally benign organic oxidant, peracetic acid, into a bio-oil that has selective antimicrobial properties against LAB and not yeasts. The resulting bio-oil demonstrated up to 90% inhibition of commercially sampled LAB (including antibiotic-resistant strains) at 4 mg ml−1 with no inhibition against an industrial yeast strain. These antimicrobial properties of the bio-oil are attributed to larger unidentified lignin oligomers, compared to monolignols, that have a membrane damaging mode of action. Using the bio-oil (4 mg ml−1) during simultaneous saccharification and fermentation (SSF) of raw corn starch showed no inhibition of enzymatic activity, and in LAB contaminated fermentations the bio-oil treatments showed an 8% increase in ethanol yields at higher bacterial contamination ratios (l : 100 yeast to LAB, CFU per ml). This study illustrates the efficacy of using lignin bio-oil as an antibiotic replacement during fuel ethanol fermentation and demonstrates the highly selective antimicrobial properties of lignin oligomers, which creates a viable lignin valorization strategy for biorefineries. |
| Databáze: | OpenAIRE |
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