Faecalibacterium duncaniae A2-165 growth is strongly promoted by yeast extract and vitamin B5 in cGMP medium.

Several gut microbial species within the Faecalibacterium genus have emerged as promising next-generation probiotics (NGP) due to their multifunctional protective effects against gastrointestinal and systemic disorders. To enable clinical studies and further applications, improved methods for cultivating Faecalibacterium must be developed in compliance with current Good Manufacturing Practice regulations, which is complicated by its oxygen sensitivity and complex nutritional requirements. Different yeast-based nutrients (YBNs), including yeast extracts (YEs) and yeast peptones (YPs), are ubiquitously used when cultivating microbes to supply a broad range of macro- and micronutrients. In this study, we evaluated six experimental YBNs, namely three YEs, two YPs and a yeast cell wall product (YCW), and eight B-vitamins in the cultivation of Faecalibacterium duncaniae A2-165, former Faecalibacterium prausnitzii, using growth assays in microtitre plates, dose-effect studies in Hungate tube fermentations and fully controlled bioreactor experiments. We demonstrated that YEs promote F. duncaniae A2-165 growth in a nutritionally limited medium, while YPs and YCW lacked essential growth factors for enabling cell propagation. High cell density was obtained in controlled bioreactors using a medium containing 2-4% of a selected YE and 1% casein peptone (3.4 ± 1.7 × 109 -5.1 ± 1.3 × 109 cells mL-1 ). Among all tested B-vitamins, we identified B5 as a strong growth promoter. Replacing casein peptone with YP and supplementing with vitamin B5 further increased biomass by approximately 50% (6.8 ± 1.7 × 109 cells mL-1 ). Hence, empirical selection of YE, YP and B5 allowed formulation of a high-yielding animal allergen-free nutritive medium to produce F. duncaniae A2-165. Selecting nutritionally suitable YBNs and combining these with other key nutrients are important steps for optimizing production of NGP with high yields and lower cost.

Enhancement of Cell-Based Vaccine Manufacturing through Process Intensification.

There are many drivers to intensify the manufacturing of vaccines. The emergence of SARS-CoV-2 has only added to them. Since the pandemic began, we have been seeing an acceleration of vaccine development and approval, including application of novel prophylactic vaccine modalities. We have also seen an increase in the appreciation and general understanding of what had been a somewhat obscure discipline. Concurrently, there has been great interest in the application of new understandings and technology to the intensification of biopharmaceutical processes in general. The marriage of these developments defines the field of vaccine manufacturing process intensification Difficulties in its implementation include the many disparate vaccine types-from conjugate to hybrid to nucleic acid based. Then, there are the respective and developing manufacturing methods, modes, and platforms-from fermentation of transformed bacteria to the bioreactor culture of recombinant animal cells to production of virus-like particles in transgenic plants. Advances are occurring throughout the biomanufacturing arena, from process development (PD) techniques to manufacturing platforms, materials, equipment, and facilities. Bioprocess intensification refers to systems for producing more product per cell, time, volume, footprint, or cost. The need for vaccine manufacturing process intensification is being driven by desires for cost control, process efficiency, and the heightened pressures of pandemic response. We are seeing great interest in the power of such disciplines as synthetic biology, process simplification, continuous bioprocessing, and digital techniques in the optimization of vaccine PD and manufacturing. Other powerful disciplines here include process automation, improved monitoring, optimized culture materials, and facility design. The intent of this short commentary is to provide a brief review and a few examples of the exciting advances in the equipment, technology, and processes supporting this activity.

S-methyl thioesters are produced from fatty acids and branched-chain amino acids by brevibacteria: focus on L-leucine catabolic pathway and identification of acyl-CoA intermediates.

Despite their importance as potent odors that contribute to the aroma of numerous cheeses, S-methyl thioesters formation pathways have not been fully established yet. In a first part of our work, we demonstrated that Brevibacterium antiquum and Brevibacterium aurantiacum could produce S-methyl thioesters using short-chain fatty acids or branched-chain amino acids as precursors. Then, we focused our work on L-leucine catabolism using liquid chromatography tandem mass spectrometry and gas chromatography-mass spectrometry analyses coupled with tracing experiments. For the first time, several acyl-CoAs intermediates of the L-leucine to thioesters conversion pathway were identified. S-methyl thioisovalerate was produced from L-leucine, indicating that this amino acid was initially transaminated. Quite interestingly, data also showed that other S-methyl thioesters, e.g., S-methyl thioacetate or S-methyl thioisobutyrate, were produced from L-leucine. Enzymatic and tracing experiments allowed for postulating catabolic pathways leading to S-methyl thioesters biosynthesis.

Identification of a powerful aroma compound in munster and camembert cheeses: ethyl 3-mercaptopropionate.

With the view to investigate the presence of thiols in cheese, the use of different methods of preparation and extraction with an organomercuric compound ( p-hydroxymercuribenzoate) enabled the isolation of a new compound. The analysis of cheese extracts by gas chromatography coupled with pulse flame photometry, mass spectrometry, and olfactometry detections led to the identification of ethyl 3-mercaptopropionate in Munster and Camembert cheeses. This compound, described at low concentrations as having pleasant, fruity, grapy, rhubarb, and empyreumatic characters, has previously been reported in wine and Concord grape but was never mentioned before in cheese. A possible route for the formation of this compound in relation with the catabolism of sulfur amino acids is proposed.