Bioprocessing, Recovery, and Mass Balance of Vegetative Lipids from Metabolically Engineered “Oilcane” Demonstrates Its Potential as an Alternative Feedstock for Drop-In Fuel Production

Abstract

Plant oils are increasingly in demand as renewable feedstocks for biodiesel and biochemicals. Currently, oilseeds are the primary source of plant oils. Although the vegetative tissues of plants express lipid metabolism pathways, they do not hyperaccumulate lipids. Elevated synthesis, storage, and accumulation of lipids in vegetative tissues have been achieved by metabolic engineering of sugarcane to produce "oilcane". This study evaluates the potential of oilcane as a renewable feedstock for the coproduction of lipids and fermentable sugars. Oilcane was grown under favorable climatic and field conditions in Florida (FLOC) as well as during an abbreviated growing season, outside its typical growing region, in Illinois (ILOC). The potential lipid yield of 0.35 tons/ha was projected from the hyperaccumulation of fatty acids in the stored vegetative biomass of FLOC, which is approaching the lipid yield of soybean (0.44 tons/ha). Processing of the vegetative tissues of oilcane recovered 0.20 tons/ha, which represents the recovery of 55% of the total lipids from FLOC. Chemical-free hydrothermal bioprocessing of ILOC and FLOC bagasse and leaves at 180 °C for 10 min prevented the degeneration of in situ plant lipids. This allowed the recovery of lipids at the end of the bioprocess with a major fraction of lipids remaining in the biomass residues after pretreatment and saccharification. Improvements through refined biomass processing, crop management, and metabolic engineering are expected to boost lipid yields and make oilcane a prime feedstock for the production of biodiesel.

Design of a High-Rate Wastewater Treatment Process for Energy and Water Recovery at Biorefineries

“…Antifoam agent was added automatically using a level sensor. Samples were regularly drawn from the broth to monitor broth sugar and ethanol concentrations using HPLC . Fermentation was terminated after fermentable sugars were depleted, and the conversion efficiency of the samples ranged from 0.44 to 0.48 g of ethanol per g of total fermentable sugars.…”

“…Samples were regularly drawn from the broth to monitor broth sugar and ethanol concentrations using HPLC. 35 Fermentation was terminated after fermentable sugars were depleted, and the conversion efficiency of the samples ranged from 0.44 to 0.48 g of ethanol per g of total fermentable sugars. After fermentation, the broth was heated to 95 °C for 2 h to evaporate ethanol and generate the spent broth samples.…”

Lipid‐enhanced Oilcane does not impact soil carbon dynamics compared with wild‐type Sugarcane

“…Lipid content, C:N ratio, and δ 13 C are provided in Table 1. Complete details on the growth and processing of the litter can be found in Maitra et al (2022).…”

“…Note: Values are mean ± SE and letters represent significant differences. 1 Data fromMaitra et al (2022).…”

Triacylglycerol, total fatty acid, and biomass accumulation of metabolically engineered energycane grown under field conditions confirms its potential as feedstock for drop‐in fuel production

“…This involved overexpression of WRI 1, DGAT 1, and OLE 1, and/or suppression of SUGAR‐DEPENDENT 1 ( SDP 1) and TRIGALACTOSYLDIACYLGLYCEROL 1 ( TGD 1) or PEROXISOMAL TRANSPORTER 1 ( PXA 1). So far only a few reports evaluated lipid producing grasses under field conditions (Beechey‐Gradwell et al., 2020, 2022; Kannan et al., 2022; Maitra et al., 2022). Here, we explore field performance for both oil and biomass yield in metabolically engineered energycane.…”