Development of a novel microplate for high-throughput screening and optimization of DHA producing strains based on CFD technology.

Microtiter plates are suitable for screening and process development of most microorganisms. They are currently the container of choice for high-throughput and small-scale microbial culture, but require optimization for specific work. In this research, a novel type of microtiter plate was developed using computational fluid dynamics (CFD) technology. The new plate provided high oxygen supply and optimal mixing effects for the fermentation culture of docosahexaenoic acid (DHA) producing strains, surpassing the conventional method of strain screening with shake flasks, which was insufficient. The shape of the microtiter plate was modified, and baffles were introduced to improve mass transfer and oxygen supply effects in the vibrating bioreactor. CFD technology was used to model the new plate's characteristics, establishing the superiority of hexagonal microtiter plates with six baffles. Parameters in the incubation process, such as vibration frequency and liquid load, were optimized, and the final result achieved an oxygen transfer coefficient (KL a) of 0.61 s-1 and a volume power input of 2364 w m-3 , which was four to five times better than the original 96-well plate. The culture results optimized by the model were also verified. Therefore, this new microtiter plate provides a powerful tool for future high-throughput screening of strains.

Development of a green fermentation strategy with resource cycle for the docosahexaenoic acid production by Schizochytrium sp.

The fermentation production of docosahexaenoic acid (DHA) is an industrial process with huge consumption of freshwater resource and nutrient, such as carbon sources and nitrogen sources. In this study, seawater and fermentation wastewater were introduced into the fermentation production of DHA, which could solve the problem of fermentation industry competing with humans for freshwater. In addition, a green fermentation strategy with pH control using waste ammonia, NaOH and citric acid as well as FW recycling was proposed. It could provide a stable external environment for cell growth and lipid synthesis while alleviating the dependence on organic nitrogen sources of Schizochytrium sp. It was proved that this strategy has good industrialization potential for DHA production, and the biomass, lipid and DHA yield reached to 195.8 g/L, 74.4 g/L and 46.4 g/L in 50 L bioreactor, respectively. This study provides a green and economic bioprocess technology for DHA production by Schizochytrium sp.

Breast and dorsal spine relapse of granulocytic sarcoma after allogeneic stem cell transplantation for acute myelomonocytic leukemia: A case report.

BACKGROUND: Granulocytic sarcoma (GS) is a rare malignant tumor, and relapse is even rarer in the breast and dorsal spine following allogeneic hematopoietic stem cell transplantation. Currently, a standard treatment regimen is not available. CASE SUMMARY: A rare case of GS of the right breast and dorsal spine after complete remission of acute myelogenous leukemia is reported here. A 55-year-old female patient presented with a palpable, growing, painless lump as well as worsening dorsal compressive myelopathy. She had a history of acute myelomonocytic leukemia (AML M4) and achieved complete remission after chemotherapy following allogeneic hematopoietic stem cell transplantation. Imaging examinations showed the breast lump and C7-T1 epidural masses suspected of malignancy. Histologic results were compatible with GS in both the right breast and dorsal spine, which were considered extramedullary relapse of the AML treated 4 years earlier. CONCLUSION: A rare case of GS relapse following allogeneic hematopoietic stem cell transplantation and guidelines for treatment are discussed.

Transcriptomic Analysis of Morphology Regulatory Mechanisms of Microparticles to Paraisaria dubia in Submerged Fermentation.

Liquid submerged fermentation is an effective strategy to achieve large-scale production of active ingredients by macrofungi, and controlling mycelium morphology is a key factor restricting the development of this technology. Mining for superior morphological regulatory factors and elucidation of their regulatory mechanisms are vital for the further development of macrofungal fermentation technology. In this study, microparticles were used to control the morphology of Paraisaria dubia (P. dubia) in submerged fermentation, and the underlying regulatory mechanisms were revealed by transcriptomic. The relative frequency of S-type pellet diameter increased significantly from 7.14 to 88.31%, and biomass increased 1.54 times when 15 g/L talc was added. Transcriptome analysis showed that the morphological regulation of filamentous fungi was a complex biological process, which involved signal transduction, mycelium polar growth, cell wall synthesis and cell division, etc. It also showed a positive impact on the basic and secondary metabolism of P. dubia. We provided a theoretical basis for controlling the mycelium morphology of P. dubia in submerged fermentation, which will promote the development of macrofungal fermentation technology.