Evaluation of engineered low-lignin poplar for conversion into advanced bioproducts

Area of Science:

• Biotechnology
• Plant Science
• Biomass Conversion

Background:

• Lignocellulosic biomass is a key feedstock for bio-based products and bioenergy.
• Biomass recalcitrance, primarily due to lignin, limits efficient conversion into sugars.
• Genetic engineering strategies aim to reduce lignin content and modify its composition to enhance biomass processability.

Purpose of the Study:

• To evaluate the impact of reduced lignin content on biomass deconstruction and bioproduct yield.
• To assess the effectiveness of QsuB expression in poplar trees for improving biomass conversion.
• To determine the potential of modified poplar biomass for producing advanced bioproducts.

Main Methods:

• Expression of bacterial 3-dehydroshikimate dehydratase (QsuB) in poplar trees to alter lignin biosynthesis.
• Ionic liquid pretreatment of engineered and wild-type poplar biomass.
• Enzymatic saccharification to release sugars from pretreated biomass.
• Fermentation of hydrolysates using engineered yeast strains for bioproduct production.

Main Results:

• Engineered poplar biomass with reduced lignin yielded significantly higher amounts of glucose and xylose after pretreatment and saccharification.
• Fermentation of hydrolysates from QsuB transgenic trees did not negatively affect yeast cell growth.
• Bioproduct titers, including α-bisabolene, epi-isozizaene, and fatty alcohols, increased by up to 58% in QsuB transgenic lines.

Conclusions:

• Poplar biomass engineered with QsuB exhibits reduced recalcitrance, facilitating improved downstream processing.
• The QsuB technology offers a viable strategy for enhancing the production of advanced bioproducts from lignocellulosic feedstocks.
• This approach holds promise for the large-scale manufacturing of bio-based products and bioenergy.