Bioconversion of non-food corn biomass to polyol esters of fatty acid and single-cell oils

Abstract

Background Lignocellulose is a valuable carbon source for the production of biofuels and biochemicals, thus having the potential to substitute fossil resources. Consolidated bio-saccharification (CBS) is a whole-cell-based catalytic technology previously developed to produce fermentable sugars from lignocellulosic agricultural wastes. The deep-sea yeast strain Rhodotorulapaludigena P4R5 can produce extracellular polyol esters of fatty acids (PEFA) and intracellular single-cell oils (SCO) simultaneously. Therefore, the integration of CBS and P4R5 fermentation processes would achieve high-value-added conversion of lignocellulosic biomass. Results The strain P4R5 could co-utilize glucose and xylose, the main monosaccharides from lignocellulose, and also use fructose and arabinose for PEFA and SCO production at high levels. By regulating the sugar metabolism pathways for different monosaccharides, the strain could produce PEFA with a single type of polyol head. The potential use of PEFA as functional micelles was also determined. Most importantly, when sugar-rich CBS hydrolysates derived from corn stover or corncob residues were used to replace grain-derived pure sugars for P4R5 fermentation, similar PEFA and SCO productions were obtained, indicating the robust conversion of non-food corn plant wastes to high-value-added glycolipids and lipids. Since the produced PEFA could be easily collected from the culture via short-time standing, we further developed a semi-continuous process for PEFA production from corncob residue-derived CBS hydrolysate, and the PEFA titer and productivity were enhanced up to 41.1 g/L and 8.22 g/L/day, respectively. Conclusions Here, we integrated the CBS process and the P4R5 fermentation for the robust production of high-value-added PEFA and SCO from non-food corn plant wastes. Therefore, this study suggests a feasible way for lignocellulosic agro-waste utilization and the potential application of P4R5 in industrial PEFA production.

Customizable and stable multilocus chromosomal integration: a novel glucose-dependent selection system in Aureobasidium spp.

“…6 with a single PFK gene, which have the potential to serve as biorefinery cell factories utilizing glucose as a carbon resource. Notably, Rhodotorula paludigena P4R5 has demonstrated the ability to accumulate 23.5 g/L polyol esters of fatty acids from 140 g/L glucose [ 44 ]. Moesziomyces aphidis XM01 can accumulate 53.9% intercellular lipid from 80 g/L glucose [ 45 ].…”

Biotransformation of Lignocellulosic Biomass to Value-Added Bioproducts: Insights into Bio-Saccharification Strategies and Potential Concerns

“…The fermentable sugars from lignocellulosic wastes have been used to produce intracellular single-cell oils and extracellular polyol ester of fatty acids (PEFA). For this purpose, Liu et al [82] reported that Rhodotorula paludigena is capable of co-utilizing xylose and glucose. The regulation of the sugar metabolism pathway for different monosaccharide strains can produce PEFA.…”

“…The regulation of the sugar metabolism pathway for different monosaccharide strains can produce PEFA. Further, the use of corncob or corn stover hydrolysates to replace pure sugars in fermentation led to high yields, indicating the facile transformation of non-food corn waste to high-value lipids and glycolipids [82]. Zheng et al [166] reported simultaneous saccharification and fermentation of cassava residues for non-toxic and biodegradable rhamnolipid biosurfactant production.…”