Hydrolyzed corn stover as a promising feedstock for 2‐phenylethanol production by nonconventional yeast

Abstract

BACKGROUND: Plant biomass rich in lignocelluloses may be applicable for the production of highly valuable bioproducts. In this study, the use of hydrolyzed corn stover as a carbon source for yeast producing 2-phenylethanol (2-PE) is investigated. 2-PE is an alcohol with a rosy scent, commonly used in the food and cosmetic industries as an aroma and preservative. The growing demand for this compound motivates the development of new methods of production. RESULTS: The corn stover biomass was first pretreated with an alkaline solution of H 2 O 2 and secondly hydrolysed with a cellulolytic enzyme cocktail to cause the saccharification of polycarbohydrates and the release of fermentable monosugars.This resulted in saccharification yields of up to 88.1 ± 7.6% and 92.5 ± 9.1% related to cellulose (glucan) and hemicellulose (arabinoxylan) content, respectively. Next, the obtained hydrolyzates were used as a feedstock for 2-PE production by two nonconventional yeasts, Metschnikowia chrysoperlae WUT25 and Pichia fermentans WUT36. The highest 2-PE titer of 3.67 g L −1 was attained with the WUT36 strain. Finally, 2-PE was extracted from the fermentation broth with ethyl acetate (100% recovery) and purified by distillation to 97.27 ± 0.08%. CONCLUSION: This is the first report demonstrating the promising and complete route of 2-PE production by yeast in a medium based on the hydrolyzate of corn stover.

Sensing, Uptake and Catabolism of L-Phenylalanine During 2-Phenylethanol Biosynthesis via the Ehrlich Pathway in Saccharomyces cerevisiae

“…Moreover, 2-PE can be synthesized by solid-state fermentation using low-cost raw materials by Pichia kudriavzevii, and the maximum 2-PE titre was 27.2 mg per gram of dry substrate (Martinez-Avila et al, 2020). Interestingly, hydrolysed corn stover or molasses can be used as a carbon source to produce 2-PE by nonconventional yeast or Bacillus licheniformis, with higher 2-PE concentrations of 3.67 g/L and 4.41 g/L, respectively (Mierzejewska et al, 2019;Zhan et al, 2020). To reduce the cost, in current studies, Escherichia coli has been developed for the biotransformation of L-Phe, glucose, or glycerol to 2-PE with resting cells, leading to a higher 2-PE concentration (9.1 g/L) from glucose or glycerol (Liu et al, 2018;Lukito et al, 2019;Sekar et al, 2019).…”

Synthesis and characterization of carbon microspheres from rubber wood by hydrothermal carbonization

“…Biomass is a sustainable source of many industrial raw materials including cellulose and carbon, and is anticipated to represent >70% of the aggregate viable energy source supply by 2030 . Plant biomass is rich in lignocelluloses, therefore, appropriate for production of highly value‐added bio‐products such as carbon and cellulose . Furthermore, conversion of biomass into carbon has emerged as an attractive alternative to traditional sources such as petroleum coke, pitch and coal .…”

Carotenoid-Producing Yeasts: Identification and Characteristics of Environmental Isolates with a Valuable Extracellular Enzymatic Activity

“…Therefore, cellulases are widely applied in various sectors, such as food, detergent, laundry, textile, baking and bio-fuels industries. However, the commercially available cellulolytic enzymes are mostly active at elevated temperature, about 40-50 • C, like one of the most popular enzyme coctail Cellic ® CTec2 and HTec2 [40]. One of the key requirements in these processes is to reduce the costs of heating, leading to a search for microorganisms, especially psychrotolerant ones, that secrete cellulases active at moderate temperatures.…”