Dynamic changes of total acid and bacterial communities during the traditional fermentation of Hong Qu glutinous rice wine

Background: Hong Qu glutinous rice wine (HQGRW) is brewed under non-aseptic fermentation conditions, so it usually has a relatively high total acid content. The aim of this study was to investigate the dynamics of the bacterial communities and total acid during the fermentation of HQGRW and elucidate the correlation between total acid and bacterial communities. Results: The results showed that the period of rapid acid increase during fermentation occurred at the early stage of fermentation. There was a negative response between total acid increase and the rate of increase in alcohol during the early fermentation stage. Bacterial community analysis using high-throughput sequencing technology was found that the dominant bacterial communities changed during the traditional fermentation of HQGRW. Both principal component analysis (PCA) and hierarchical clustering analysis revealed that there was a great difference between the bacterial communities of Hong Qu starter and those identified during the fermentation process. Furthermore, the key bacteria likely to be associated with total acid were identified by Spearman's correlation analysis. Lactobacillus, unclassified Lactobacillaceae, and Pediococcus were found, which can make significant contributions to the total acid development (| r| N 0.6 with FDR adjusted P b 0.05), establishing that these bacteria can associate closely with the total acid of rice wine. Conclusions: This was the first study to investigate the correlation between bacterial communities and total acid during the fermentation of HQGRW. These findings may be helpful in the development of a set of fermentation techniques for controlling total acid.

The Mutagenesis of Lactobacillus Thermophilus for Enhanced L-(+)-Lactic Acid Accumulation Induced by Heavy Ion Irradiation

ABSTRACT Screening promising L. thermophiles with high productivity, high efficiency and strong adaptability are very important in lactic acid industry. For this purpose, 80MeV/u carbon ions were applied to irradiate L. thermophiles. After high-throughput screening, a mutant, named SRZ50, was obtained. Different carbon sources or nitrogen sources were provided to investigate carbon or nitrogen source utilization between mutant SRZ50 and wild type, and different fermentation periods were also chose to study fermentation characteristic between mutant SRZ50 and wild type. The results showed that mutant SRZ50 exhibited the enhanced L-(+)-lactic acid production from wild type. When glucose or fructose was the sole carbon source, the L(+)-lactic acid production by mutant SRZ50 was both the highest, respectively, 23.16 ± 0.72 g/L or 23.24 ± 0.66 g/L, which had a significant increase from that of wild type (P<0.01), following obvious increase in biomass (P<0.05). When yeast powder was the sole nitrogen source, it can promote mutant SRZ50 to accumulate the highest L-(+)-lactic acid accumulation, which also had a significant increase from that of wild type (P<0.01). Under different fermentation periods, it was obtained that mutant SRZ50 all exhibited significant increase in L-(+)-lactic acid accumulation from wild type. In conclusion, a mutant strain with improved production profiles for L-(+)-lactic acid, was obtained, indicating that heavy ions can be an efficient tool to improve metabolic product accumulations in microbes.

L-(+)-Lactic acid production by Lactobacillus rhamnosus B103 from dairy industry waste

ABSTRACT Lactic acid, which can be obtained through fermentation, is an interesting compound because it can be utilized in different fields, such as in the food, pharmaceutical and chemical industries as a bio-based molecule for bio-refinery. In addition, lactic acid has recently gained more interest due to the possibility of manufacturing poly(lactic acid), a green polymer that can replace petroleum-derived plastics and be applied in medicine for the regeneration of tissues and in sutures, repairs and implants. One of the great advantages of fermentation is the possibility of using agribusiness wastes to obtain optically pure lactic acid. The conventional batch process of fermentation has some disadvantages such as inhibition by the substrate or the final product. To avoid these problems, this study was focused on improving the production of lactic acid through different feeding strategies using whey, a residue of agribusiness. The downstream process is a significant bottleneck because cost-effective methods of producing high-purity lactic acid are lacking. Thus, the investigation of different methods for the purification of lactic acid was one of the aims of this work. The pH-stat strategy showed the maximum production of lactic acid of 143.7 g/L. Following purification of the lactic acid sample, recovery of reducing sugars and protein and color removal were 0.28%, 100% and 100%, respectively.

Enhanced solubilization of iron and calcium phosphates by Aspergillus niger by the addition of alcohols

The present study deals with the effect of increased concentrations of alcohols (methanol and ethanol) on the solubilization of FePO4 and CaHPO4 by Aspergillus niger. The efficiency of solubilization (ES) of inorganic phosphates, fungal growth, acid production and pH variation were determined. The concentrations of alcohols that most favored the solubilization of phosphates were 4% methanol and 3% ethanol. The ES of phosphates by the fungus in media containing methanol ranged from 11-96% and 0.4-87% for ethanol. The stimulation or inhibition of solubilization was dependent on greater or lesser fungus growth, acid production and decreased pH. These responses were supported by the correlation between the amount of phosphate dissolved and fungal growth (0.630** to 0.831**), the production of acids (0.529* to 0.989**) and a decrease in pH (-0.755** to -0.962**). Thus, the addition of alcohols facilitated insoluble phosphates dissolution during the fungus growth.

In vitro effect of xylitol on proliferation and acid production of oral candida / 第二军医大学学报

Objective To investigate the in vitro effect of xylitol on the proliferation and acid production of oral Candida, and so as to explore new prophylaxis methods against oral fungal infection. Methods Pathogenic oral Candida were clinically harvested, cultured and purified in laboratory from the saliva of 100 patients wearing dentures. The proliferation and acid production of 4 types of commonly-seen Candida albicans (C. albicans), Candida glabrata, Candida tropicalis and Candida krusei, were observed inSabouraud's glucose medium, with glucose replacedby different concentrations of xylitol (ratios of glucose and xylital being 4:1, 3:2, 2:3, 1:4, and 0: 5), so as to evaluate the inhibitory effect of xylitol on the growth of different kinds of Candida. At the same time, the proliferation and acid production of C. albicans were compared when cultured with different concentrations (5%, 10%, 15%, and 20%) of xylitol (experimental groups) for 6, 12, 24, 48, and 72 h under aerobic and anoxic conditions. Results The D600 values of four kinds of Candida in pure xylitol culture media were significantly lower and pH values were significantly higher compared with those in the glucose combined with xylitol culture media (P< 0. 05). Under aerobic condition, compared with the group without xylitol, the pH values in the experimental groups with different concentrations of xylitol were significantly higher and the Deoo values were significantly lower (P < 0. 05), except for the D600 values at 48 and 72 h with 5% xylitol, D6oo value at 48 h with 10% xylitol, and pH value at 48 h with 5% xylitol. Under anoxic condition, D600 values were all significanlty increased and the pH values were all significantly decreased at all time points in the experimental groups (P < 0.05). Conclusion Xylitol can significantly inhibit the proliferation and acid production of the four common Candida species, suggesting that xylitol may serve as a substitute of sugar and inhibitor of pathogenic Candida and may play an important role in preventing and controlling oral infections of pathogenic Candida.

In vitro antibiotic effect of the leaching solution of astragalus on cariogenic bacteria / 实用口腔医学杂志

Astragalus produced in Gansu were chosen as the raw material to leachate. Studied the antibiotic effects of the leaching solution on the cariogenic bacteria and compared with the imported bacteriostatic product MI. Streptococcus mutans and Lactobacilli were cultured in the medium for 24 h. The PH and A600 values were measured. Statistical analysis was conducted by using SPSS 13.0. The leaching solution of astragalus has the same inhibitory effects on the growth and acid production of streptococcus mutans and lactobacilli as MI.

Inhibition effect of methylene blue on acid productin metabolism in in vitro plaque glycolysis modles / 实用口腔医学杂志

0.05, vs group ③). Conclusion:Methylene may inhiit production of plaque in a time independat way.

Study on Encapsulation Efficiency and In-vitro Release of Glycyrrhetinic Acid Liposomes / 广州中医药大学学报

Objective To determine the encapsulation efficiency of glycyrrhetinic acid(GA) liposomes and to study the release of GA from the liposomes in vitro.Methods GA liposomes were prepared by ethanol injection.The unencapsulated glycyrrhetinic acid and liposomes were separated by sephadex gel G-50,and the encapsulation efficiency was detected by HPLC.The release behavior of the drug was studied by the third method for dissolution issued in Chinese pharmacopoeia(published in 2005).Results The encapsulation efficiency of liposomes was 91.61%,and the in-vitro drug-release curve was accorded with Higuchi equation.Conclusion The GA liposomes have high encapsulation efficiency and sustained-release effect.

Lactic Acid Production and Antagonistic Effect of Lactic Acid Bacteria from Piglet Intestine / 微生物学通报

Lactic acid production and antagonistic property of five strains of LAB isolated from piglet intestine were investigated. The results showed that among all strains L5 exhibited the most rapid production and highest amount of lactic acid in the culture. Consequently, the pH in L5 culture showed the fast decline, with the final value significantly lower than those of other cultures. Strain L1 showed the least production of lactic acid and highest pH among all strains. Culture supernatants of the five strains showed different degrees of antagonistic effect against pathogenic E. coli K88, K99, 987P, O141, E1, and S. aureus. When taking out the effect of the acid, the culture supernatants still showed 22%～53% inhibitory effect, suggesting that the bacteria produced other inhibitory substances apart from lactic acid. The inhibitory effect of the culture supernatant was above 92% after heat treatment and above 85% when treated with proteases.

THE EFFECTS OF PROPANOIC ACID ACCUMULATION ON THE GROWTH AND ACID-PRODUCTION OF PROPIONIBACTERIUM SHERMANII / 微生物学通报

The effects of propanoic acid accumulation on the growth and acid production of Propionibacterium shermanii are reported in this paper, the glucose consumption, acid production and cell growth curve are measured in the batch fermentation process with 6%glucose serves as carbon source and pH value controlled at 6 5 If 1%, 3%, and 6% propanoic acid are added to the broth 24 hours after inoculation, the cell dry weights obtained at the end of the fermentation change to 75 3%, 65 4%, 52 9% of the CK respectively, at the same time, the acid accumulation becomes 79 3%, 69 2%, 39 3% of the CK respectively But even 6% propanoic acid is added, the glucose consumption and acid production could not be stopped completely The cell dry weight increased 60% if part of the propanoic acid is removed from the broth and replaced by fresh medium