Selection of Saccharomyces cerevisiae strains for efficient very high gravity bio-ethanol fermentation processes

An optimized very high gravity (VHG) glucose medium supplemented with low cost nutrient sources was used to evaluate bio-ethanol production by 11 Saccharomyces cerevisiae strains. The industrial strains PE-2 and CA1185 exhibited the best overall fermentation performance, producing an ethanol titre of 19.2% (v/v) corresponding to a batch productivity of 2.5 g l-1 h-1, while the best laboratory strain (CEN.PK 113-7D) produced 17.5% (v/v) ethanol with a productivity of 1.7 g l-1 h-1. The results presented here emphasize the biodiversity found within S. cerevisiae species and that naturally adapted strains, such as PE-2 and CA1185, are likely to play a key role in facilitating the transition from laboratory technological breakthroughs to industrialscale bio-ethanol fermentations.Fundação para a Ciência e a Tecnologia (FCT) - PTDC/BIO/66151/2006, SFRH/ BD/64776/2009, SFRH/BPD/44328/ 200

Engineering of ecological niches to create stable artificial consortia for complex biotransformations

The design of controllable artificial microbial consortia has attracted considerable interest in recent years to capitalize on the inherent advantages in comparison to monocultures such as the distribution of the metabolic burden by division of labor, the modularity and the ability to convert complex substrates. One promising approach to control the consortia composition, function and stability is the provision of defined ecological niches fitted to the specific needs of the consortium members. In this review, we discuss recent examples for the creation of metabolic niches by biological engineering of resource partitioning and syntrophic interactions. Moreover, we introduce a complementing process engineering approach to provide defined spatial niches with differing abiotic conditions (e.g. O2, T, light) in stirred tank reactors harboring biofilms. This enables the co-cultivation of microorganisms with non-overlapping abiotic requirements and the control of the strain ratio in consortia characterized by substrate competition

A heterogeneous microbial consortium producing short-chain fatty acids from lignocellulose.

Microbial consortia are a promising alternative to monocultures of genetically modified microorganisms for complex biotransformations. We developed a versatile consortium-based strategy for the direct conversion of lignocellulose to short-chain fatty acids, which included the funneling of the lignocellulosic carbohydrates to lactate as a central intermediate in engineered food chains. A spatial niche enabled in situ cellulolytic enzyme production by an aerobic fungus next to facultative anaerobic lactic acid bacteria and the product-forming anaerobes. Clostridium tyrobutyricum, Veillonella criceti, or Megasphaera elsdenii were integrated into the lactate platform to produce 196 kilograms of butyric acid per metric ton of beechwood. The lactate platform demonstrates the benefits of mixed cultures, such as their modularity and their ability to convert complex substrates into valuable biochemicals

Quantitative proteomic analysis of the influence of lignin on biofuel production by Clostridium acetobutylicum ATCC 824

Background: Clostridium acetobutylicum has been a focus of research because of its ability to produce high-value compounds that can be used as biofuels. Lignocellulose is a promising feedstock, but the lignin–cellulose–hemicellulose biomass complex requires chemical pre-treatment to yield fermentable saccharides, including cellulose-derived cellobiose, prior to bioproduction of acetone–butanol–ethanol (ABE) and hydrogen. Fermentation capability is limited by lignin and thus process optimization requires knowledge of lignin inhibition. The effects of lignin on cellular metabolism were evaluated for C. acetobutylicum grown on medium containing either cellobiose only or cellobiose plus lignin. Microscopy, gas chromatography and 8-plex iTRAQ-based quantitative proteomic technologies were applied to interrogate the effect of lignin on cellular morphology, fermentation and the proteome. Results: Our results demonstrate that C. acetobutylicum has reduced performance for solvent production when lignin is present in the medium. Medium supplemented with 1 g L−1 of lignin led to delay and decreased solvents production (ethanol; 0.47 g L−1 for cellobiose and 0.27 g L−1 for cellobiose plus lignin and butanol; 0.13 g L−1 for cellobiose and 0.04 g L−1 for cellobiose plus lignin) at 20 and 48 h, respectively, resulting in the accumulation of acetic acid and butyric acid. Of 583 identified proteins (FDR < 1 %), 328 proteins were quantified with at least two unique peptides. Up- or down-regulation of protein expression was determined by comparison of exponential and stationary phases of cellobiose in the presence and absence of lignin. Of relevance, glycolysis and fermentative pathways were mostly down-regulated, during exponential and stationary growth phases in presence of lignin. Moreover, proteins involved in DNA repair, transcription/translation and GTP/ATP-dependent activities were also significantly affected and these changes were associated with altered cell morphology. Conclusions: This is the first comprehensive analysis of the cellular responses of C. acetobutylicum to lignin at metabolic and physiological levels. These data will enable targeted metabolic engineering strategies to optimize biofuel production from biomass by overcoming limitations imposed by the presence of lignin

Consolidated bioprocessing of lignocellulosic biomass to lactic acid by a synthetic fungal-bacterial consortium

Consolidated bioprocessing (CBP) of lignocellulosic feedstocks to platform chemicals requires complex metabolic processes, which are commonly executed by single genetically engineered microorganisms. Alternatively, synthetic consortia can be employed to compartmentalize the required metabolic functions among different specialized microorganisms as demonstrated in this work for the direct production of lactic acid from lignocellulosic biomass. We composed an artificial cross‐kingdom consortium and co‐cultivated the aerobic fungus Trichoderma reesei for the secretion of cellulolytic enzymes with facultative anaerobic lactic acid bacteria. We engineered ecological niches to enable the formation of a spatially structured biofilm. Up to 34.7 gL−1 lactic acid could be produced from 5% (w/w) microcrystalline cellulose. Challenges in converting pretreated lignocellulosic biomass include the presence of inhibitors, the formation of acetic acid and carbon catabolite repression. In the CBP consortium hexoses and pentoses were simultaneously consumed and metabolic cross‐feeding enabled the in situ degradation of acetic acid. As a result, superior product purities were achieved and 19.8 gL−1 (85.2% of the theoretical maximum) of lactic acid could be produced from non‐detoxified steam‐pretreated beech wood. These results demonstrate the potential of consortium‐based CBP technologies for the production of high value chemicals from pretreated lignocellulosic biomass in a single step

Roaring to Softly Whispering: X-Ray Emission after ∼3.7 yr at the Location of the Transient AT2018cow and Implications for Accretion-powered Scenarios

We present the first deep X-ray observations of luminous fast blue optical transient (LFBOT) AT 2018cow at ∼3.7 yr since discovery, together with the reanalysis of the observation at δt ∼ 220 days. X-ray emission is significantly detected at a location consistent with AT 2018cow. The very soft X-ray spectrum and sustained luminosity are distinct from the spectral and temporal behavior of the LFBOT in the first ∼100 days and would possibly signal the emergence of a new emission component, although a robust association with AT 2018cow can only be claimed at δt ∼ 220 days, while at δt ∼ 1350 days contamination of the host galaxy cannot be excluded. We interpret these findings in the context of the late-time panchromatic emission from AT 2018cow, which includes the detection of persistent, slowly fading UV emission with νLν ≈ 1039 erg s−1. Similar to previous works (and in analogy with arguments for ultraluminous X-ray sources), these late-time observations are consistent with thin disks around intermediate-mass black holes (with M• ≈ 103–104M☉) accreting at sub-Eddington rates. However, differently from previous studies, we find that smaller-mass black holes with M• ≈ 10–100 M☉ accreting at ≳the Eddington rate cannot be ruled out and provide a natural explanation for the inferred compact size (Rout ≈ 40 R☉) of the accretion disk years after the optical flare. Most importantly, irrespective of the accretor mass, our study lends support to the hypothesis that LFBOTs are accretion-powered phenomena and that, specifically, LFBOTs constitute electromagnetic manifestations of super-Eddington accreting systems that evolve to ≲Eddington over a ≈100-day timescale

Metabolic Effects Of Duodenojejunal Bypass Surgery In A Rat Model Of Type 1 Diabetes

Background Metabolic surgery has beneficial metabolic effects, including remission of type 2 diabetes. We hypothesized that duodenojejunal bypass (DJB) surgery can protect against development of type 1 diabetes (T1D) by enhancing regulation of cellular and molecular pathways that control glucose homeostasis. Methods BBDP/Wor rats, which are prone to develop spontaneous autoimmune T1D, underwent loop DJB (n = 15) or sham (n = 15) surgery at a median age of 41 days, before development of diabetes. At T1D diagnosis, a subcutaneous insulin pellet was implanted, oral glucose tolerance test was performed 21 days later, and tissues were collected 25 days after onset of T1D. Pancreas and liver tissues were assessed by histology and RT-qPCR. Fecal microbiota composition was analyzed by 16S V4 sequencing. Results Postoperatively, DJB rats weighed less than sham rats (287.8 vs 329.9 g,P = 0.04). In both groups, 14 of 15 rats developed T1D, at similar age of onset (87 days in DJB vs 81 days in sham,P = 0.17). There was no difference in oral glucose tolerance, fasting and stimulated plasma insulin and c-peptide levels, and immunohistochemical analysis of insulin-positive cells in the pancreas. DJB rats needed 1.3 +/- 0.4 insulin implants vs 1.9 +/- 0.5 in sham rats (P = 0.002). Fasting and glucose stimulated glucagon-like peptide 1 (GLP-1) secretion was elevated after DJB surgery. DJB rats had reduced markers of metabolic stress in liver. After DJB, the fecal microbiome changed significantly, including increases inAkkermansiaandRuminococcus, while the changes were minimal in sham rats. Conclusion DJB does not protect against autoimmune T1D in BBDP/Wor rats, but reduces the need for exogenous insulin and facilitates other metabolic benefits including weight loss, increased GLP-1 secretion, reduced hepatic stress, and altered gut microbiome

Implementation of a Cost and Variation Reduction Program for Hemostasis Products at a Large Academic Medical Center: A Multi-Stakeholder Perspective

Tejen Shah,1 Stacy Brethauer,1 Walter A Danker III,2 Ishita Doshi,2 Matthew O’Hara,3 Abigail Silber,3 William K Vasileff4 1Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA; 2Ethicon, Inc., Raritan, NJ, USA; 3Trinity Life Sciences, Waltham, MA, USA; 4Department of Orthopaedics, Sports Medicine Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USACorrespondence: Stacy Brethauer, Email [email protected]: Cost-saving initiatives targeting surgical supplies management have become increasingly common to address rising healthcare costs. However, few studies provide details on hospital stakeholder experiences or learnings from implementing such initiatives. Thus, we sought to evaluate hospital stakeholder satisfaction with conversion to a sole supplier for hemostasis products, in addition to economic and clinical impacts, to help develop best practices for implementation.Methods: This cross-sectional study assessed satisfaction with converting to a sole supplier for hemostasis products at a large US academic medical center using qualitative interviews and quantitative surveys with clinical and non-clinical stakeholders, on the decision-making process, conversion, and vendor-supported hemostasis optimization program (HOP) post-implementation (February 2022–May 2022). Perioperative hemorrhage events, adjunctive hemostat utilization, and total annual hospital expenditure on hemostatic products were also evaluated pre- and post-conversion (2020– 2022) to identify impacts on clinical and economic outcomes.Findings: Ten hospital stakeholders completed qualitative interviews (n = 7 surgeons, n = 2 surgical technicians, n = 1 administrator) and 22 completed quantitative surveys (n = 6 surgeons, n = 5 surgical technicians, n = 11 nurses). Survey respondents noted overall satisfaction with conversion, including the level of input they provided in the decision-making process (75% were somewhat to extremely satisfied), availability of hemostatic agents during the conversion process (87%), and the vendor-supported HOP (100%). The outcomes analyses revealed a nearly 25% decrease in supply expenditure without changes to the number of postoperative hemorrhage events following implementation.Practical Applications: Converting to a sole vendor for hemostasis products was achieved with high satisfaction among hospital stakeholders and cost savings to the institution without impacting the quality of patient care. This study provides a roadmap of best practices for other institutions interested in implementing similar initiatives and presents an example of a successful transition to a sole vendor for hemostasis products driven by effective supplier, institution, and hospital stakeholder coordination.Keywords: hemostatic agent, cost savings, variation reduction, surgical care, hospital inventor

Foregut exclusion enhances incretin and insulin secretion after Roux-en-Y gastric bypass in adults with type 2 diabetes

Introduction: Patients with type 2 diabetes experience resolution of hyperglycemia within days after Roux-en-Y gastric bypass (RYGB) surgery.This is attributed, in part, to enhanced secretion of hindgut factors following exclusion of the gastric remnant and proximal intestine during surgery. However, evidence of the mechanisms of remission remain limited due to the challenges of metabolic evaluation during the early postoperative period. The purpose of this investigation was to determine the role of foregut exclusion in the resolution of type 2 diabetes after RYGB. Methods: Patients with type 2 diabetes (n = 15) undergoing RYGB had a gastrostomy tube (G-tube) placed in their gastric remnant at time of surgery. Patients were randomized to receive a mixed meal tolerance test via oral or G-tube feeding immediately prior to and 2 weeks after surgery in a repeated measures crossover design. Plasma glucose, insulin, C-peptide, incretin responses, and indices of meal-stimulated insulin secretion and sensitivity were determined. Results: Body weight, fat mass, fasting glucose and insulin, and circulating lipids were significantly decreased 2 weeks after surgery. The glycemic response to feeding was reduced as a function of total area under the curve but not after adjustment for the reduction in fasting glucose. Oral feeding significantly enhanced insulin and incretin secretion after RYGB, which was entirely ablated by G-tube feeding. Conclusion: Foregut exclusion accounts for the rise in incretin and insulin secretion but may not fully explain the early improvements in glucose metabolism after RYGB surgery