Bioproduction of L-piperazic acid in gram scale using Aureobasidium melanogenum

Currently, piperazic acid is chemically synthesized using ecologically unfriendly processes. Microbial synthesis from glucose is an attractive alternative to chemical synthesis. In this study, we report the production of L-piperazic acid via microbial fermentation with the first engineered fungal strain of Aureobasidium melanogenum; this strain was constructed by chassis development, genetic element reconstitution and optimization, synthetic rewiring and constitutive genetic circuit reconstitution, to build a robust L-piperazic acid synthetic cascade. These genetic modifications enable A. melanogenum to directly convert glucose to L-piperazic acid without relying on the use of either chemically synthesized precursors or harsh conditions. This bio-based process overcomes the shortcomings of the conventional synthesis routes. The ultimately engineered strain is a very high-efficient cell factory that can excrete 1.12 ± 0.05 g l-1 of L-piperazic acid after a 120-h 10.0-l fed-batch fermentation; this is the highest titre of L-piperazic acid reported using a microbial cell factory

Metabolic engineering of clostridium cellulovorans to improve butanol production by consolidated bioprocessing.

Clostridium cellulovorans DSM 743B can produce butyrate when grown on lignocellulose, but it can hardly synthesize butanol. In a previous study, C. cellulovorans was successfully engineered to switch the metabolism from butyryl-CoA to butanol by overexpressing an alcohol aldehyde dehydrogenase gene adhE1 from Clostridium acetobutylicum ATCC 824; however, its full potential in butanol production is still unexplored. In the study, a metabolic engineering approach based on a push-pull strategy was developed to further enhance cellulosic butanol production. In order to accomplish this, the carbon flux from acetyl-CoA to butyryl-CoA was pulled by overexpressing a trans-enoyl-coenzyme A reductase gene (ter), which can irreversibly catalyze crotonyl-CoA to butyryl-CoA. Then an acid reassimilation pathway uncoupled with acetone production was introduced to redirect the carbon flow from butyrate and acetate toward butyryl-CoA. Finally, xylose metabolism engineering was implemented by inactivating xylR (Clocel_0594) and araR (Clocel_1253), as well as overexpressing xylT (CA_C1345), which is expected to supply additional carbon and reducing power for CoA and butanol synthesis pathways. The final engineered strain produced 4.96 g/L of n-butanol from alkali extracted corn cobs (AECC), increasing by 235-fold compared to that of the wild type. It serves as a promising butanol producer by consolidated bioprocessing

Resource-aware whole-cell model of division of labour in a two-strain consortium for complex substrate degradation

Background Low-cost sustainable feedstocks are essential for commercially viable biotechnologies. These feedstocks, often derived from plant or food waste, contain a multitude of different complex biomolecules which require multiple enzymes to hydrolyse and metabolise. Current standard biotechnology uses monocultures in which a single host expresses all the proteins required for the consolidated bioprocess. However, these hosts have limited capacity for expressing proteins before growth is impacted. This limitation may be overcome by utilising division of labour (DOL) in a consortium, where each member expresses a single protein of a longer degradation pathway. Results Here, we model a two-strain consortium, with one strain expressing an endohydrolase and a second strain expressing an exohydrolase, for cooperative degradation of a complex substrate. Our results suggest that there is a balance between increasing expression to enhance degradation versus the burden that higher expression causes. Once a threshold of burden is reached, the consortium will consistently perform better than an equivalent single-cell monoculture. Conclusions We demonstrate that resource-aware whole-cell models can be used to predict the benefits and limitations of using consortia systems to overcome burden. Our model predicts the region of expression where DOL would be beneficial for growth on starch, which will assist in making informed design choices for this, and other, complex-substrate degradation pathways

Application of Shaken Lattice Interferometry Based Sensors to Space Navigation

High-sensitivity shaken lattice interferometry (SLI) based sensors have the potential to provide deep space missions with the ability to precisely measure non-gravitational perturbing forces. This work considers the simulation of the OSIRIS-REx mission navigation in the vicinity of Bennu with the addition of measurements from onboard SLI-based accelerometers. The simulation is performed in the Jet Propulsion Laboratory's (JPL) Mission Analysis, Operations and Navigation Toolkit (MONTE) and incorporates OSIRIS-REx reconstructed trajectory and attitude data from the Navigation and Ancillary Information Facility (NAIF) database. The use of the reconstructed data from NAIF provides realistic true dynamical errors and JPL's MONTE software allows for a high-fidelity simulation of a nominal reference for the filter. The navigation performance and reduction of tracking and complex modeling enabled by the onboard SLI-based sensor are presented for two orbital phases of the OSIRIS-REx mission. Overall, the results show that the addition of SLI-based accelerometer measurements improves navigation performance, when compared to a radiometric tracking only configuration. In addition, results demonstrate that highly-precise accelerometer measurements can effectively replace at least one day of DSN passes over a three-day period, thereby reducing tracking requirements. Furthermore, it is shown that lower-fidelity surface force modeling and parameter estimation is required when using onboard SLI-based accelerometers.Comment: 30 pages, 8 figure

TargeTron technology applicable in solventogenic clostridia: Revisiting 12 years’ advances

Clostridium has great potential in industrial application and medical research. But low DNA repair capacity and plasmids transformation efficiency severely delayed development and application of genetic tools based on homologous recombination (HR). TargeTron is a gene editing technique dependent on the mobility of group II introns, rather than homologous recombination, which made it very suitable for gene disruption of Clostridium. The application of TargeTron technology in Clostridium was academically reported in 2007 and this tool has been introduced in various clostridia as it is easy to operate, time-saving, and reliable. TargeTron has made great progress in solventogenic Clostridium in the aspects of acetone-butanol-ethanol (ABE) fermentation pathway modification, important functional genes identification, and xylose metabolic pathway analysis & reconstruction. In the review, we revisited 12 years' advances of TargeTron technology applicable in solventogenic Clostridium, including its principle, technical characteristics, application and efforts to expand its capabilities, or to avoid potential drawbacks. Some other technologies as putative competitors or collaborators are also discussed. We believe that TargeTron combined with CRISPR/Cas-assisted gene/base editing and gene-expression regulation system will make a better future for clostridial genetic modification

A Machine-Designed Optical Lattice Atom Interferometer

Performing interferometry in an optical lattice formed by standing waves of light offers potential advantages over its free-space equivalents since the atoms can be confined and manipulated by the optical potential. We demonstrate such an interferometer in a one dimensional lattice and show the ability to control the atoms by imaging and reconstructing the wavefunction at many stages during its cycle. An acceleration signal is applied and the resulting performance is seen to be close to the optimum possible for the time-space area enclosed according to quantum theory. Our methodology of machine design enables the sensor to be reconfigurable on the fly, and when scaled up, offers the potential to make state-of-the art inertial and gravitational sensors that will have a wide range of potential applications

Metabolic engineeringof Yarrowia lipolytica to produce chemicals and fuels from xylose

Yarrowia lipolytica is a biotechnological chassis for the production of a range of products, such as microbial oils and organic acids. However, it is unable to consume xylose, the major pentose in lignocellulosic hydrolysates, which are considered a preferred carbon source for bioprocesses due to their low cost, wide abundance and high sugar content. Here, we engineered Y. lipolytica to metabolize xylose to produce lipids or citric acid. The overexpression of xylose reductase and xylitol dehydrogenase from Scheffersomyces stipitis were necessary but not sufficient to permit growth. The additional overexpression of the endogenous xylulokinase enabled identical growth as the wild type strain in glucose. This mutant was able to produce up to 80 g/L of citric acid from xylose. Transferring these modifications to a lipid-overproducing strain boosted the production of lipids from xylose. This is the first step towards a consolidated bioprocess to produce chemicals and fuels from lignocellulosic materials

Evolution from Late Miocene to present-day of sandy deposits on mixed depositional systems in the Gulf of Cadiz

Póster presentado en Mixed / hybrid systems (Turbidite, MTDs and Contourites) on continental margin. Lisbon (Portugal), 21-22 June, 2023This work contributes to improve the knowledge of deep marine deposits, specifically those generated by the interaction of gravitational sedimentary processes and bottom currents (mixed processes). The study of these mixed deposits is of great relevance both in the academic world, and in the industry, due to their potential as energy resources and for carbon dioxide (CO2) storage. However, there is still a great lack of knowledge about their diagnostic criteria, how they are generated, how they evolve, and their socio-economic implications. Offshore seismic reflection and logging data analyses from the continental slope of the Gulf of Cadiz reveal Late Miocene and Pliocene-Quaternary contourite and mixed deposits that host sandy bodies of special interest as potential geological storages. In general, it has been observed that the sandier deposits, exhibiting high-amplitude reflections (HARs), are located mainly on the erosional elements of these depositional systems or in the transition between the erosional and the depositional features: a) contourite channels (or moats and furrows); b) in the proximal setting of contourite terraces; and c) at the exits of the Gibraltar Strait. The sandier deposits in these systems are brought into the channels/moats and terraces by gravitational processes; and once inside they are reworked by the bottom currents, being laterally transported and deposited by a higher velocity core of the current along it. The contourite and mixed deposits generated before the full opening of the Gibraltar Strait, during the Late Miocene (~8.2-5.33 Ma), display different depositional and erosional features related to the paleo-Mediterranean Outflow Water (MOW) circulating through the Betic and Rifian corridors prior to the restriction of the Mediterranean-Atlantic gateway. Natural gamma-ray logs from exploration wells in this area show sand deposits up to 50 m thick, except in wells close to the Miocene paleo-shore where alternating deposits of sand and clay are identified. After the opening of the Gibraltar Strait, the Mediterranean Outflow Water (MOW) has generated a complex Pliocene-Quaternary (5.33 Ma-present) contourite depositional system. Sampling of sandy contourites associated with seismic features also suggests the extensive distribution of mature, well-sorted Pliocene¿Quaternary sand about 600 m thick, and showing the following characteristics: a) Early Pliocene deposits (~5.3-3.2 Ma), correspond to sheeted drifts developed mixed with gravitational sedimentary processes and low acoustic response; b) Late Pliocene-early Quaternary deposits (~3.2-2 Ma) displaying sheeted contourite drifts and enhanced acoustic response towards the top, especially in areas adjacent to highs and banks. Borehole logs for these deposits show cyclic swings in amplitude that are generally lower than those observed for the overlying Quaternary deposits; c) Natural gamma-ray logs along the Quaternary sequence show medium-amplitude cyclic swings, varying on decimetre to sub-meter scale, with no major steps in base levels. The main differences of LM sandy deposits respect to the recent succession, consist of higher thicknesses, better-sorted and higher grain size of the sands, and increasing medium-high amplitude on seismic reflections. The Miocene and Pliocene deposits also exhibit cyclic swings in gamma ray logs, but with lower amplitude and at lower frequencies than those observed for the Quaternary ones

Late Miocene to present-day Sandy deposits in the Gulf of Cadiz associated to the Mediterranean Outflow Water

Póster presentado en 4th Deep-Water Circulation Research Conference (4DWC) , Edinburgh, 24-26 May 2023This work contributes to improve the knowledge of deep marine deposits, specifically those generated by the interaction of gravitational sedimentary processes and bottom currents (mixed processes). The study of these deposits is of great relevance both in the academic world, and in the industry, due to their potential as energy resources and for carbon dioxide (CO2) storage. However, there is still a great lack of knowledge about their diagnostic criteria, how they are generated, how they evolve, and their socio-economic implications. Offshore seismic reflection and logging data analyses from the continental slope of the Gulf of Cadiz reveal Late Miocene and Pliocene-Quaternary contourite and mixed deposits that host sandy bodies of special interest as potential geological storages. In general, it has been observed that the sandier deposits, exhibiting high-amplitude reflections (HARs), are located mainly on the erosional elements of these depositional systems or in the transition between the erosional and the depositional features: a) contourite channels (or moats and furrows); b) in the proximal setting of contourite terraces; and c) at the exits of the Gibraltar Strait. The sandier deposits in these systems are brought into the channels/moats and terraces by gravitational processes; and once inside they are reworked by the bottom currents, being laterally transported and deposited by a higher velocity core of the current along it. The contourite and mixed deposits generated before the full opening of the Gibraltar Strait, during the Late Miocene (~8.2-5.33 Ma), display different geometries and correspond to depositional features such as sheeted, plastered, confined, mounded and mixed drifts, as well as levees, and erosional features such as furrows, contourite and turbidite channels. These features are related to the paleo-Mediterranean Outflow Water (MOW) circulating through the Betic and Rifian corridors prior to the restriction of the Mediterranean-Atlantic gateway. Natural gamma-ray logs from exploration wells in this area show sand deposits up to 50 m thick, except in wells close to the Miocene paleo-shore where alternating deposits of sand and clay are identified. After the opening of the Gibraltar Strait, the Mediterranean Outflow Water (MOW) has generated a complex Pliocene-Quaternary (5.33 Ma-present) contourite depositional system