Developing a sustainable process for the cleaner production of baker's yeast: An approach towards waste management by an integrated fermentation and membrane separation process.

Baker's yeast industries generate highly polluted effluents, especially the cell free broth (i.e., vinasse) characterized by high chemical oxygen demand, nitrogen, and salts. In this work, it was found that the residual by-products (i.e., ethanol and acetic acid) and salts in the vinasse severely inhibited the cell growth, which hindered the reuse of the vinasse for the production of Saccharomyces cerevisiae. Through optimizing a suitable control strategy, the productions of ethanol and acetic acid were eliminated. Then, a nanofiltration membrane (i.e., NF5) was preferred for preliminarily and simultaneously separating and concentrating valuable molecules (i.e., invertase, food grade proteins and pigments) in the vinasse, and the main fouling mechanism was cake layer formation. Subsequently, a reverse osmosis membrane (RO) was suitable to separate and concentrate salts in the NF5 permeate, where the membrane fouling was negligible. Finally, the RO permeate was successfully reused for the production of S. cerevisiae. In addition, without calculating the benefit from the recovery of the valuable molecules, the cost of the integrated process can be decreased by 59.8% compared with the sole triple effect evaporation. Meanwhile, the volume of the fresh water used in the fermentation process can be decreased by 68.8%. Thus, it is a sustainable process for the cleaner production of baker's yeast using the integrated fermentation and membrane separation process.

Anticancer and antibacterial flavonoids from the callus of Ampelopsis grossedentata; a new weapon to mitigate the proliferation of cancer cells and bacteria.

A new flavonoid angelioue (1) together with five known compounds cuminatanol (2), myricetin (3), epigallocatechin (4), taxifolin (5) and dihydromyricetin (6) was isolated from the callus extract of Ampelopsis grossedentata (Hand.-Mazz.) W. T. Wang and the structures were elucidated based on their detailed spectroscopic data. Among the compounds, the new compound angelioue (1) displayed significant antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) with the MIC value of 6.68 µg mL-1 and MBC value of 53.42 µg mL-1; in contrast the other compounds showed moderate to no antibacterial activity. In addition, known dihydromyricetin (6) exhibited potent cytotoxic activities against mouse breast cancer cells (4T1), human lung adenocarcinoma (A549) and human non-small cell lung cancer (NCI-H1975) tumor cell lines with GI50 values of 17.47, 18.91 and 20.50 µM mL-1, respectively. The compounds 1-5 exhibited low micro-molar inhibitory activities. Moreover, the structure-activity relationships of the most active compounds for antibacterial and cytotoxic activities are discussed. The present findings clearly suggest that the A. grossedentata callus is a good source of bioactive compounds.

Pattern recognition of Chinese flue-cured tobaccos by an improved and simplified K-nearest neighbors classification algorithm on near infrared spectra.

In tobacco industry of China, tobacco leaves are classified and managed in terms of their cultivation areas and plant parts of tobacco-stalks. However, sometimes intentionally or involuntary mislabeling cultivation areas, blending tobacco plant parts would occur into tobacco market. The error will affect the style and quality of cigarettes. In the present work, more than 1000 Chinese flue-cured tobacco leaf samples, which have 12 genotypes and cultivated from 5 to 10 regions of China in 2003 and 2004, have been discriminated by means of an improved and simplified KNN classification algorithm (IS-KNN) based on near infrared (NIR) spectra. An original method of optimizing number of significant principal components (PCs) based on analysis of error and cross-validation was advanced. Compared with conventional pattern recognition methods KNN, NN, LDA and PLS-DA, IS-KNN exhibits good adaptability in discrimination of complicated Chinese flue-cured tobaccos. The practice in this work shows that optimized number of PCs and performance of classification models are closely relative to complicated extent of samples but not to number of categories or samples. The results demonstrated the usefulness of NIR spectra combined with chemometrics as an objective and rapid method for the authentication and identification of tobacco leaves or other kinds of powder samples.