Single cell protein and oil production from solid cocoa fatty acid distillates co-fed ethanol.

The use of solid lipid sidestreams have been overlooked as a feedstock for the production of microbial biomass for food and feed applications and little to no recent work has examined the utilization of solid fatty acid distillates (FADs), which are a significant residue from vegetable oil processing. Yarrowia lipolytica and Rhodosporidium toruloides cultivated on cocoa fatty acid distillates (CFAD) generated final cell dry weight values > 40 g/L, with strong productivity (3.3 g/L·h) and rich protein (>45%) and lipid content (>25%). Interestingly, microbial oils were > 65% unsaturated fatty acids, compared < 20% unsaturated content in FAD. Importantly, to overcome mass-transfer limitations associated with bioconversion of solid lipid residues, ethanol was applied as a co-substrate to solubilize FAD residues. Here, FAD residues from cocoa deodorization have been demonstrated to be high energy feedstocks that represent an attractive substrate for the production of both single cell protein and oil (SCPO).

Co-culture of Kluyveromyces marxianus and Meyerozyma guilliermondii with In Situ Product Recovery of 2-Phenylethanol.

Production of 2-phenylethanol (2-PE) via Kluyveromyces marxianus is well-established. However, co-culture with other microbes in combination with in situ product recovery (ISPR) yields improved selectivity and volumetric productivity. Fermentation ofK. marxianus (MUCL 53775) with direct inclusion of absorptive polymer Hytrel3548 achieved ISPR, but accumulation of the byproduct phenylethyl acetate (PEA) was strongly favored. Co-culture of K. marxianus (MUCL 53775) with Meyerozyma guilliermondii (MUCL 28072) with ISPR limited PEA production, thereby improving the 2-PE selectivity from 13 to 90%, compared to a pure culture of K. marxianus (MUCL 53775) under similar conditions. This improved the volumetric productivity by 85% compared to 2-PE ISPR with a pure culture of K. marxianus. This is the first report of co-culture in a two-phase fermentation for 2-PE bioproduction and demonstrates that interactions between co-culture and ISPR techniques can modulate bioproduction between 2-PE and byproduct PEA, and this technique will be explored for other strain combinations and for other high-value molecules of interest.

Microbial Utilization of Next-Generation Feedstocks for the Biomanufacturing of Value-Added Chemicals and Food Ingredients.

Global shift to sustainability has driven the exploration of alternative feedstocks beyond sugars for biomanufacturing. Recently, C1 (CO2, CO, methane, formate and methanol) and C2 (acetate and ethanol) substrates are drawing great attention due to their natural abundance and low production cost. The advances in metabolic engineering, synthetic biology and industrial process design have greatly enhanced the efficiency that microbes use these next-generation feedstocks. The metabolic pathways to use C1 and C2 feedstocks have been introduced or enhanced into industrial workhorses, such as Escherichia coli and yeasts, by genetic rewiring and laboratory evolution strategies. Furthermore, microbes are engineered to convert these low-cost feedstocks to various high-value products, ranging from food ingredients to chemicals. This review highlights the recent development in metabolic engineering, the challenges in strain engineering and bioprocess design, and the perspectives of microbial utilization of C1 and C2 feedstocks for the biomanufacturing of value-added products.

Correction: Lacto-N-tetraose synthesis by wild-type and glycosynthase variants of the ß-N-hexosaminidase from Bifidobacterium bifidum.

Correction for 'Lacto-N-tetraose synthesis by wild-type and glycosynthase variants of the ß-N-hexosaminidase from Bifidobacterium bifidum' by Katharina Schmölzer et al., Org. Biomol. Chem., 2019, DOI: 10.1039/c9ob00424f.

Lacto-N-tetraose synthesis by wild-type and glycosynthase variants of the ß-N-hexosaminidase from Bifidobacterium bifidum.

Lacto-N-biose 1,2-oxazoline was prepared chemo-enzymatically and shown to be a donor substrate for ß-1,3-glycosylation of lactose by the wild-type and glycosynthase variants (D320E, D320A, Y419F) of Bifidobacterium bifidum ß-N-hexosaminidase. Lacto-N-tetraose, a core structure of human milk oligosaccharides, was formed in 20-60% yield of donor substrate (up to 8 mM product titre), depending on the degree of selectivity control by the enzyme used.

APP-A Novel Player within the Presynaptic Active Zone Proteome.

The amyloid precursor protein (APP) was discovered in the 1980s as the precursor protein of the amyloid A4 peptide. The amyloid A4 peptide, also known as A-beta (Aß), is the main constituent of senile plaques implicated in Alzheimer's disease (AD). In association with the amyloid deposits, increasing impairments in learning and memory as well as the degeneration of neurons especially in the hippocampus formation are hallmarks of the pathogenesis of AD. Within the last decades much effort has been expended into understanding the pathogenesis of AD. However, little is known about the physiological role of APP within the central nervous system (CNS). Allocating APP to the proteome of the highly dynamic presynaptic active zone (PAZ) identified APP as a novel player within this neuronal communication and signaling network. The analysis of the hippocampal PAZ proteome derived from APP-mutant mice demonstrates that APP is tightly embedded in the underlying protein network. Strikingly, APP deletion accounts for major dysregulation within the PAZ proteome network. Ca2+-homeostasis, neurotransmitter release and mitochondrial function are affected and resemble the outcome during the pathogenesis of AD. The observed changes in protein abundance that occur in the absence of APP as well as in AD suggest that APP is a structural and functional regulator within the hippocampal PAZ proteome. Within this review article, we intend to introduce APP as an important player within the hippocampal PAZ proteome and to outline the impact of APP deletion on individual PAZ proteome subcommunities.