In this study, an introduction of viable cell sensor and electronic nose into ethanol fermentation was investigated, which could be used to real-time and on-line monitor the amount of living cells and product content. Compared to the conventional off-line biomass determination, the capacitance value exhibited a completely consistent trend with colony forming units, indicating that the capacitance value could reflect the living cells in the fermentation broth. On the other hand, in comparison to the results of off-line determination by high performance liquid chromatography, the ethanol concentration measured by electronic nose presented an excellent consistency, so as to realize the on-line monitoring during the whole process. On this basis, a dynamic feeding strategy of glucose guided by the changes of living cells and ethanol content was developed. And consequently, the ethanol concentration, productivity and yield enhanced by 15.4%, 15.9% and 9.0%, respectively. The advanced sensors adopted herein to monitor the key parameters of ethanol fermentation process could be readily extended to an industrial scale and other similar fermentation processes.

Objective The sorB gene related to sorbicillinoid production was used as the target, and the free expression element AMA1 was used to verify the availability of using this element in Acremonium chrysogenum. Result The point mutation of the sorB gene was successfully achieved in the Cripsr-Cas9 episomal expression system. In addition, the addition of sorB donor DNA in this system could achieve efficient, markless, and complete knockout of genes. Using this gene-editing platform, four BSSS-related genes Δaxl1, Δaxl2, Δbud3, and Δbud4 were knocked out completely, and it was found that the yield, dry weight, and pH of the knockout strains did not change significantly. Further, the stress tolerance of the knockout strains was determined, and the relationship between morphology and stress tolerance was preliminarily analyzed. Conclusion The gene-editing efficiency exceeded 80% and the developmental process of arthrospores differed from the starting strain.

The ‘design-build-test-learn’ (DBTL) cycle has been adopted in rational high-throughput screening for obtaining high-yield industrial strains. However, the mismatch between build and test slows the DBTL cycle due to the lack of high-throughput analytical technologies. In this study, a highly-efficient, accurate, and non-invasive detection method of gentamicin (GM) was developed, which can provide timely feedback for the high-throughput screening of high-yield strains. Firstly, a self-made tool was established to obtain datasets in 24-well ​based on the coloring of cells. Subsequently, the random forest (RF) algorithm was found to have the highest prediction accuracy with 98.5% for the training and 91.3% for verification. Finally, a stable genetic high-yield strain (998U/mL) was successfully screened out in 3005 mutants, which was verified to improve the titer by 72.7% in a 5 L bioreactor. Moreover, the verified new datasets were updated to the model database in order to improve learning ability of DBTL cycle.

Sophorolipids (SLs) are regarded as one of the most promising biosurfactants. They have a low toxicity and are easily degradable without polluting the environment. However, high production costs are the main obstacle to extended SLs application. Semi-continuous fermentation is a promising technology for achieving high SLs productivity, which is based on in-situ separation. In this study, the sedimentation mechanism of SLs was analyzed. The formation of a hydrophobic mixture of SLs and oil was a key factor

In this study, the effect of biosurfactant sophorolipids on Rhizomucor miehei lipase (RML) fermentation by Aspergillus oryzae was investigated. With the exogenous addition of 0.3% (w/v) sophorolipids in the initial medium, the RML activity reached 430.0 U/mL, an increase of 25.0% compared to the control group. Subsequently, the physiological metabolic responses of A. oryzae to the addition of sophorolipids were further explored. The results showed that although sophorolipids had almost no effect on the RML secretion, it would affect the morphology of the cells. During the late phase of the fermentation, the proportion of middle pellets, which were generally considered as an energetic and stable state for enzyme production was increased with the addition of sophorolipids. Simultaneously, the viscosity of fermentation broth was reduced, thereby contributing to the oxygen transfer and RML production. Finally, it could be found that the addition of sophorolipids significantly increased the content of precursor amino acids, especially for those rank first and second of the RML composition, and it could promote the synthesis of RML.