Study On The Characters Of Fluorescence Spectra Of Probiotics

The probiotics are very beneficial to human health, which can be taken as food additive, and maintain the balance of intestinal flora. It is the application of probiotics to obtain good medical effects, health effects, and achieve economic, social and ecological benefits. In order to benefit mankind by the application of probiotics, further studies need to be done. There are a lot of reports about the fluorescence of bacteria abroad, which are about the fluorescence spectra of bacteria with low concentration, and identifying bacteria by the method of principal component analysis. But there are no reports about the fluorescence of probiotics at home, and the studies of this paper fill in the blank. The combination of fluorescence analysis and the study of probiotics is a new perspective of studying the characteristics of probiotics, and provide more reference value about the research of probiotics.We used physical method to study the fluorescence spectra of Lactobacillus plantarum, Streptococcus thermophilus, Lactobacillus casei, Latobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus mutans, and provided reference for the application of fluorescence in the qualitative and quantitative investigation of probiotics. The fluorescence of Lactobacillus plantarum solution were characterized by two- dimensional fluorescence spectroscopy and three-dimensional fluorescence spectroscopy, and the fluorescence intensities of different concentrations of Lactobacillus plantarum solution were quantitative detected, while the fluorescence polarization technology was used to study Lactobacillus plantarum. Comparing and analyzing the zero-order derivative fluorescence spectra of Lactobacillus casei and Streptococcus thermophilus, as well as the spectral characteristics of the second-order derivative fluorescence spectra, and giving the differences between the two strains. Combination of radial basis function (RBF) neural network algorithm, we identified the spectra of Lactobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus mutans. Introducing the application of optical tweezers in studying fluorescence spectrometry of probiotics, and the experiments of this part will be achieved in the next step as the result of the current experimental conditions.The absorption spectra and fluorescence spectra of Lactobacillus Plantarum are measured and studied by spectral analysis technique, and the results will be applied to the study and classification of probiotic bacteria. The results show that Lactobacillus Plantarum absorbs ultraviolet rays and emits obvious fluorescence in the range of 300nm and 650nm. There are four peaks in this range, and the locations are 338nm, 387nm, 465nm and 535nm respectively, these correspond to the major organic material in cells: aromatic amino, nucleotide, NADH, FAD, FMN and so on. The studies of the spectra show relevant information in cells about Lactobacillus Plantarum. The relations between fluorescence intensities and the concentrations are also studied and the change law of intensity with increasing concentration is found. The functions of data fitting based on the law are shown in this article. The relationship between the intensity change of two peaks (em1 and em2) and concentration is non-linear, but the other two (em3 and em4) are linear. The studies of Lactobacillus Plantarum provide reference for the research on the application of fluorescence analysis in the field of bacteria, and also provide experimental data for realizing identification of strains via fluorescence spectra. With the frontal experiment, we studied the excitation spectra and polarization spectroscopy in the 300nm-430nm range of Lactobacillus plantarum solution. The experimental results show that the polarization degrees of the two peaks are 0.4485 and 0.0921 respectively. The first peak embodies a certain polarization, but the polarization degree of the second is very low. The mechanism of energy transfer between different fluorophore was used to explain the reason of the small polarization degree of the second peak.From the research, we found that the fluorescence spectra of Lactobacillus casei-BDI are similar to Streptococcus thermophilus. It is difficult to identify the two strains from the spectra directly. Second-order spectra can reduce the interference and increase the resolving power. According to the results, with the excitation wavelengths of 285nm and 340nm, there are significant differences between the Second-order spectra.Using wavelet transform and RBF neural network method to process experimental data and identify three different probiotics. The data were compressed by wavelet transform, which reduced the amount of data and maintained the spectral characteristics of the peak, but also reduced the neural network processing time. Neural network was used to process compressed data, and identify the spectra, which can achieve computerization and automation, and the results showed that this method of identification of probiotics is accurate.Finally, the principle of optical tweezers was introduced and the applications in probiotics study of single-cell were also introduced briefly. Capturing Lactobacillus acidophilus cells by optical tweezers, and achieving cell captured and moved. The combination of optical tweezers and fluorescence analysis can reduce cell movement and Brownian motion interference and improve signal-to-noise ratio. Studying the single cell in the condition closing to the natural physiological state can obtain the information of single life's components and real-time and biochemical changes information in groups under the average individual.In this paper, the research has enriched the fluorescence spectroscopy application areas. Combined with three-dimensional technology, polarization, derivative fluorescence, wavelet analysis, radial basis function neural network algorithm, the applications of fluorescence analysis in studies of probiotics are improved and enhanced. Providing a basis for further research on probiotics and a meaningful reference for the wide applications of fluorescence analysis technology...