Bioprocess and Biosystems Engineering

Libertellenone H (1) was a promising antitumor diterpenoid isolated from Arctic fungus Eutypella sp. D-1, however, its production was very limited. In this study, we investigated the effects of ethanol on cell growth and libertellenone H production. The mycelium in ethanol-feeding cultures was fragmented and dispersed, and the titer of libertellenone H was remarkably increased to 4.88 mg l−1 in an optimal feeding manner, which was 16.4-fold higher than the control group. To provide an insight into the cell response to ethanol, genes critical to the libertellenone H biosynthesis were successfully cloned and their transcription levels were determined. The results suggested that the gene transcription levels of 3-hydroxy-3-methyl glutaric acyl coenzyme A reductase and geranylgeranyl diphosphate synthase were up-regulated by ethanol stimulation. The results from this study were helpful for further understanding of the ethanol function on diterpenes biosynthesis as well as developing more effective strategies for over-production of these desired secondary metabolites.

Nanogold of 10 nm was used to label carcinoembryonic antigen antibody (CEAAb) to prepare a probe (Au-CEAAb) for carcinoembryonic antigen (CEA). In a Na2HPO4–NaH2PO4 buffer solution of pH 6.8, CEA reacted with Au-CEAAb to form a big Au-CEAAb–CEA immunocomplex that can be removed by centrifugation. The unreacted Au-CEAAb in the centrifugal supernatant exhibited catalytic effect on the Cu2O particle reaction, and the Cu2O particles displayed a resonance scattering (RS) peak at 602 nm. When CEA increased, the RS intensity at 602 nm decreased, and the decreased RS intensity (ΔI 602 nm) was linear to CEA concentration (C CEA) in the range of 0.02–12 ng mL−1, with the regression equation of ΔI 602 nm = 27.1 C CEA + 3.3, correlation coefficient of 0.9978 and detection limit of 3 pg mL−1 CEA. The proposed method was applied to detect CEA in real samples, with satisfactory results.

Molecular docking is an important computational analysis widely used to predict the interaction of enzymes with several starting materials for developing new valuable products from several starting materials, including oils and fats. In the present study, molecular docking was used as an efficient in silico screening tool to select biocatalysts with the highest catalytic performance in butyl esters production in a solvent-free system, an eco-friendly approach, via direct esterification of free fatty acids from Licuri oil with butanol. For such purpose, three commercial lipase preparations were used to perform molecular docking studies such as Burkholderia cepacia (BCL), Porcine pancreatic (PPL), and Candida rugosa (CRL). Concurrently, the results obtained in BCL and CRL are the most efficient in the esterification process due to their higher preference for catalyzing the esterification of lauric acid, the main fatty acid found in the licuri oil composition. Meanwhile, PPL was the least efficient because it preferentially interacts with minor fatty acids. Molecular docking with the experimental results indicated the better performance in the synthesis of esters was BCL. In conclusion, experimental results analysis shows higher enzymatic productivity in esterification reactions of 1294.83 μmol/h.mg, while the CRL and PPL demonstrated the lowest performance (189.87 μmol / h.mg and 23.96 μmol / h.mg, respectively). Thus, molecular docking and experimental results indicate that BCL is a more efficient lipase to produce fatty acids and esters from licuri oil with a high content of lauric acid. In addition, this study also demonstrates the application of molecular docking as an important tool for lipase screening to achieve more sustainable production of butyl esters with a view synthesis of biolubricants.

Previous modelling of the pullulan fermentation is discussed and found to lack any mechanistic basis. It is concluded that predictive ability can only be conferred by a structured model with at least two “compartments”, based upon the best available knowledge of the physiology of the microorganism. Such a model is constructed and compared with experimental data.

The effects of different osmotic pressure, changed by six salts (NaCl, Na2SO4, (NH4)2SO4, KH2PO4 and MSG), on cell growth and DHA synthesis by Schizochytrium sp. were investigated. Six optimal mediums were obtained to study different osmotic pressure combinations at cell growth stage and DHA synthesis stage. Results showed that cultivated cell in higher osmotic pressure condition and fermented in lower osmotic pressure condition was benefit to enhance DHA synthesis. Combination 17-6 could get the maximum cell dry weight of 56.95 g/L and the highest DHA percentage in total fatty acids of 55.21 %, while combination 17-B could get the highest lipid yield of 33.47 g/L with 42.10 % DHA in total fatty acids. This was the first report about the enhancement of DHA production by osmotic regulation and this work provided two novel osmotic control processes for high lipid yield and high DHA percentage in total fatty acids.

 Manufacture of VAQTA®, an inactivated hepatitis A vaccine, uses state-of-the-art technologies in cell culture and bioprocessing science, which have made it possible to routinely produce the vaccine at manufacturing scale. VAQTA® consists of an attenuated strain of hepatitis A virus that is highly purified and formaldehyde-inactivated, then formulated with an aluminum hydroxide adjuvant. Process development and scale-up have resulted in a well-characterized vaccine manufacturing process with appropriate in-process controls to assure consistent performance, and a reproducible, well-defined product. Results are presented from a series of manufacturing demonstration lots to show consistency, as well as comparability to clinical lots prepared at an earlier stage in development.