In-situ monitoring of saccharides removal of alcohol precipitation using near-infrared spectroscopy

As unsafe components in herbal medicine(HM),saccharides can affect not only the drug appearance and stabilization,but also the drug efficacy and safety.The present study focuses on the in-line monitoring of batch alcohol precipitation processes for saccharide removal using nearinfrared(NIR)spectroscopy.NIR spectra in the 4000–10,000-cm^(-1)wavelength range are acquired in situ using a transflectance probe.These directly acquired spectra allow characterization of the dynamic variation tendency of saccharides during alcohol precipitation.Calibration models based on partial least squares(PLS)regression have been developed for the three saccharide impurities,namely glucose,fructose,and sucrose.Model errors are estimated as the root-meansquare errors of cross-validation(RMSECVs)of internal validation and root-mean-square errors of prediction(RMSEPs)of external validation.The RMSECV values of glucose,fructose,and sucrose were 1.150,1.535,and 3.067 mg·mL^(-1),and the RMSEP values were 0.711,1.547,and 3.740 mg·mL^(-1),respectively.The correlation coeffcients(r)between the NIR predictive and the reference measurement values were all above 0.94.Furthermore,NIR predictions based on the constructed models improved our understanding of sugar removal and helped develop a control strategy for alcohol precipitation.The results demonstrate that,as an alternative process analytical technology(PAT)tool for monitoring batch alcohol precipitation processes,NIR spectroscopy is advantageous for both efficient determination of quality characteristics(fast,in situ,and requiring no toxic reagents)and process stability,and evaluating the repeatability.

Separation of 1,3-propanediol from glycerol-based fermentations of Klebsiella pneumoniae by alcohol precipitation and dilution crystallization

The separation of 1,3-propanediol from the glycerol-based fermentation broth of Klebsiella pneumoniae plays an important role during the microbial production of 1,3-propanediol.In this paper,the separation of 1,3-propanediol from fermentative broth by a combination of ultrafiltration and alcohol dilution crystallization was investi-gated.The broth was first filtered by ultrafiltration,and 99%of cells,89.4%of proteins and 69%of nucleic acids were removed.The obtained broth was further condensed by vacuum distillation,and then alcohol was added.The macro-molecular impurities,such as nucleic acids,polysaccharides and proteins,were precipitated,and inorganic and organic salts were crystallized.The optimal volume ratio of alcohol added to the condensed fermentation broth was determined to be 2:1.As a result,proteins,nucleic acids and electric conduc-tivity decreased by 97.4%,89.7%and 95.8%,respectively,compared with the fermentative broth.The influences of pH and water content in condensed broth on alcohol precipi-tation and dilution crystallization were also investigated.The experimental results indicated that alcohol precipitation and dilution crystallization was feasible and effective for the separation of 1,3-propanediol from actual fermentation broth.

Optimization of extraction process of Amomum longiligulare T.L.Wu polysaccharides by response surface methodology

Objective:To optimize the technological conditions of ultrasonic-assisted extraction of Amomum longiligulare T.L.Wu polysaccharides and increase the yield of polysaccharides.Methods:The polysaccharide was prepared by water extraction and alcohol precipitation method,and the yield of polysaccharide was taken as an index.The effects of ultrasonic time,extraction times,ultrasonic temperature,and water-to-material ratio on polysaccharide yield were investigated through a single factor experiment.Combined experimental design and response surface analysis were used to optimize the extraction process of Amomum longiligulare T.L.Wu polysaccharides.Results:The optimum conditions of ultrasonic-assisted extraction were determined as follows:extraction time of 29 min,three extraction times,water bath extraction temperature of 68℃,water-to-material ratio of 15:1;under these conditions,the polysaccharide yield was 10.69%.Conclusion:The results are close to the predicted values of the model.This optimization test is effective and feasible,and provides a reference for the related research of Amomum longiligulare T.L.Wu.