Globally, biofuel and oleochemical production based on plant oils negatively affects biodiversity. As an alternative triglyceride source, lipid production from oleaginous yeasts faces numerous challenges in feedstock availability, lipid productivity, downstream processing, and waste treatment, prohibiting the design of a cost-competitive process with regard to plant equivalents. In this study, we present a fully integrated operation for microbial oil production, which consolidates upstream and downstream processing with side-stream recycling. Co-fermentation of sugar and acetic acid was successfully implemented in fed-batch, semi-continuous, and continuous fermentation modes. Process validation was conducted at a 25 L scale with a lipid productivity of 1.2 g L⁻¹ h⁻¹. Cutaneotrichosporon oleaginosus cell debris was used as an inducer in Trichoderma reesei fermentation for on-site generation of yeast-specific cell-wall hydrolases. In situ hydrolase application allowed for efficient C. oleaginosus cell lysis (85% w/w) and simultaneous lipid release. A subsequent centrifugation step yielded 90% (w/w) recovery of intracellular lipids without the need for any organic solvent. The nutrient-rich water phase was applied as an internal sugar source for subsequent yeast fermentation cycles. With this yeast hydrolysate, the lipid productivity was considerably increased to 2.4 g L⁻¹ h⁻¹. A techno-economic analysis of the current lipid production processes estimated costs at $1.6 per kg lipid. Moreover, life cycle assessment analysis indicated an emission of 3.56 kg CO₂ equivalents for every 1 kg produced yeast oil. Accordingly, we established an integrated operation for bioconversion of acetic acid and sugar to sustainable lipids at maximum productivity coupled with minimal waste generation and energy consumption.

A novel oligochitosan/DMSO system as a green sorbent for CO₂capturing.

78 million tons of residual seagrass deposits accumulate annually on shorelines worldwide. These represent an untapped feedstock for fermentative single‐cell oil production, targeted at biofuel and oleochemical generation, without affecting the sensitive marine environment or compromising food security. Seven beach‐cast samples of seagrass (related to Z. marina, Z. noltii, S. filiforme, P. australis, P. oceanic, and T. testudinum) were collected from marine ecosystems around the world. A combination of 18S rRNA phylogenetic, structural, and comprehensive biomass analyses of seagrass leaves were applied. The carbohydrate content ranged from 73 to 81 % (w/^dw_biomass). Single‐step enzymatic hydrolysis was developed to efficiently release the monomeric sugars contained in seagrasses biomass without any pretreatment. P. oceanica hydrolysate allowed for higher lipid yields (6.8 g L⁻¹) compared to the synthetic minimal medium (5.1 g L⁻¹) in shake flasks, and was subsequently utilized as the sole fermentation medium for oleaginous yeast T. oleaginosus at a technical scale using a fed‐batch bioreactor, which provided 24.5 g L⁻¹ lipids (0.35 g L⁻¹ h⁻¹). Moreover, the sugar/lipid conversion ratio was 0.41 (w/w). Cumulative data indicates that by exploiting only half of the global beach‐cast seagrass, approximately 4 million tons of microbial oils could be generated.

Flaxseeds are typically consumed either as whole flaxseed, ground flaxseed, flaxseed oil, partially defatted flaxseed meal, or as a milk alternative. They are considered a rich source of vitamins, minerals, proteins and peptides, lipids, carbohydrates, lignans, and dietary fiber, which have shown hypolipidemic, antiatherogenic, anticholesterolemic, and anti-inflammatory property activity. Here, an in vitro batch culture model was used to investigate the influence of whole milled flaxseed and partially defatted milled flaxseed press cake on the gut microbiota and the liberation of flaxseed bioactives. Microbial communities were profiled using 16S rRNA gene-based high-throughput sequencing with targeted mass spectrometry measuring lignan, cyclolinopeptide, and bile acid content and HPLC for short-chain fatty acid profiles. Flaxseed supplementation decreased gut microbiota richness with Firmicutes, Proteobacteria, and Bacteroidetes becoming the predominant phyla. Secoisolariciresinol, enterodiol, and enterolactone were rapidly produced with acetic acid, butyric acid, and propionic acid being the predominant acids after 24 h of fermentation. The flaxseed press cake and whole flaxseed were equivalent in microbiota changes and functionality. However, press cake may be superior as a functional additive in a variety of foods in terms of consumer acceptance as it would be more resistant to oxidative changes.

Cutaneotrichosporon oleaginosus is a highly efficient single cell oil producer, which in addition to hexoses and pentoses can metabolize organic acids. In this study, fed-batch cultivation with consumption-based acetic acid feeding was further developed to integrate the transformation of an industrial paper mill lignocellulosic hydrolysate (LCH) into yeast oil. Employing pentose-rich LCH as a carbon source instead of glucose significantly improved both biomass formation and lipid titer, reaching 55.73 ± 5.20 g/L and 42.1 ± 1.7 g/L (75.5% lipid per biomass), respectively. This hybrid approach of using acetic acid and LCH in one process was further optimized to increase the share of bioavailable carbon from LCH using a combination of consumption-based and continuous feeding. Finally, the techno-economic analysis revealed a 26% cost reduction when using LCH instead of commercial glucose. In summary, we developed a process leading to a holistic approach to valorizing a pentose-rich industrial waste by converting it into oleochemicals.