Enhanced adsorption of Orange II on bagasse-derived biochar by direct addition of CTAB

Guo-Ting Liang,Huiyuan Li,Xiao Mi,Weigao Zhao 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.8

Surface charge properties of an adsorbent always play an important role for the removal of contaminants from water. A cationic surfactant hexadecyl tri-methyl ammonium bromide (CTAB) was involved into adsorptive removal of Orange II (ORII) by bagasse biochars to realize an in-situ modification and an enhanced adsorption capability. Adsorption capacity of biochar (BC600) improved significantly from 1.66mg/g in the absence of CTAB to 4.42mg/g in the presence of 2.0mg/L CTAB. A more hydrophobic surface of bagasse biochar was favorable for the dye uptake in the presence of CTAB. Linear pseudo-second-order kinetic model fitted the kinetics data better at three pH conditions than pseudo-first-order kinetic model, whether in the presence and absence of CTAB. Both nonlinear pseudo-first-order and pseudo-second-order kinetic models were suitable to describe the experimental data. The maximal adsorption capacity in the absence of CTAB was very limited (41.4mg/g), while the adsorption isotherm curve in the presence of CTAB was almost linear, indicating a strong adsorption capability due to the introduction of CTAB. Direct addition of CTAB into wastewater is a potential technique for the enhanced removal of negatively-charged pollutants by bagasse biochar.

Dynamics of Bacterial Communities of Lamb Meat Packaged in Air and Vacuum Pouch during Chilled Storage

Taojun Wang,Huiyuan Guo,Hao Zhang,Fazheng Ren,Ming Zhang,Shaoyang Ge,Hailing Luo,Liang Zhao 한국축산식품학회 2019 한국축산식품학회지 Vol.39 No.2

In this study, the changes in microbial communities of lamb meat packaged in the air (plastic tray, PT) and in a vacuum pouch (VAC) were assessed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) during the storage at 4°C. For the PT lamb, the total viable count (TVC) was 107 CFU/g on Day 5, and the dominated bacteria were Pseudomonas fragi, P. fluorescens, and Acinetobacter spp. For the VAC lamb, the TVC was 107 CFU/g on Day 9, and the dominated bacteria were lactic acid bacteria, including Carnobacterium divergens, C. maltaromaticum, and Lactococcus piscium. One strain of Pseudomonas spp. also appeared in VAC lamb. The relative abundance of Enterobacteriaceae in VAC lamb was higher than that PT lamb, indicating a more important role of Enterobacteriaceae in spoilage for VAC lamb than that of PT lamb. The microbial compositions changed faster in the lamb stored in a PT than that stored in a VAC, and microbial community compositions of the late storage period were largely different from those of the early storage period for both the conditions. The findings of this study may guide improve the lamb hygiene and prolong the shelf life of the lamb.

Safety Evaluation of Lactobacillus paracasei subsp. paracasei LC-01,a Probiotic Bacterium

Hao Zhang,Yu Wang,Jing Sun,Zirui Guo,Huiyuan Guo,Fazheng Ren 한국미생물학회 2013 The journal of microbiology Vol.51 No.5

The safety of Lactobacillus paracasei subsp. paracasei LC-01was evaluated for its use as a potential probiotic. In our in vitro study, the antibiotic resistance and the ability to produce biogenic amine were determined. The results showed that the strain was sensitive to all tested antibiotics and did not produce biogenic amine except for tyramine. The oral toxicity of this strain was evaluated in Balb/C mice. One hundred mice were divided into 10 groups. Four groups were administered 0, 108, 109, or 1010 CFU/mouse per day dissolved in saline solution respectively, for 28 days. Three groups were injected intraperitoneally with 109 CFU/mouse dissolved in saline solution, and were killed 2, 5, and 10 days after injection. The last 3 groups were injected with the vehicle as controls respectively. The results showed that oral administration of the strain had no adverse effects on mouse body weight and that there was no treatment-associated bacterial translocation. Intraperitoneal administration caused a significant translocation to liver, spleen and kidney. However,this translocation did not cause illness or death throughout the experiment. The results suggest that L. paracasei subsp. paracasei LC-01 is likely to be safe for human consumption.

Purification and properties of a milk-clotting enzyme produced by Bacillus amyloliquefaciens D4

Xiaoling He,Bozhong Gan,Fazheng Ren,Huiyuan Guo,Weibing Zhang,Xi Song 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.1

The milk-clotting enzyme from Bacillus amyloliquefaciens D4 was purified to 17.2-fold with 20% recovery by precipitation in ammonium sulfate and ion-exchange chromatography. The molecular mass of the enzyme was 58.2kDa as determined by SDS-PAGE, and it was proved to be a metalloprotease by EDTA inhibition. The enzyme was active in the pH range 5.5-7.0 and was inactivated completely by heating at 55℃ for 20 min. The highest level of enzyme activity was obtained at 65 ℃, pH 5.5, in the presence of 25mM CaCl_2. The milk-clotting activity was inhibited only slightly by Na^+ and K^+ and significantly by Cu^(2+), Zn^(2+) and Sn^(2+). The Km value of this enzyme was 0.471 mg/mL. The high level of milk-clotting activity coupled with a low level of thermal stability suggested that the milk-clotting enzyme from B. amyloliquefaciens D4 should be considered as a potential substitute for calf rennet.

Lactobacillus salivarius Strain FDB89 Induced Longevity in Caenorhabditis elegans by Dietary Restriction

Yang Zhao,Liang Zhao,Xiaonan Zheng,Tianjiao Fu,Huiyuan Guo,Fazheng Ren 한국미생물학회 2013 The journal of microbiology Vol.51 No.2

In this study, we utilized the nematode Caenorhabditis elegans to assess potential life-expanding effect of Lactobacillus salivarius strain FDB89 (FDB89) isolated from feces of centenarians in Bama County (Guangxi, China). This study showed that feeding FDB89 extended the mean life span in C. elegans by up to 11.9% compared to that of control nematodes. The reduced reproductive capacities, pharyngeal pumping rate, growth, and increased superoxide dismutase (SOD)activity and XTT reduction capacity were also observed in FDB89 feeding worms. To probe the anti-aging mechanism further, we incorporated a food gradient feeding assay and assayed the life span of eat-2 mutant. The results demonstrated that the maximal life span of C. elegans fed on FDB89was achieved at the concentration of 1.0 mg bacterial cells/plate, which was 10-fold greater than that of C. elegans fed on E. coli OP50 (0.1 mg bacterial cells/plate). However, feeding FDB89 could not further extend the life span of eat-2mutant. These results indicated that FDB89 modulated the longevity of C. elegans in a dietary restriction-dependent manner and expanded the understanding of anti-aging effect of probiotics.

Bioactive Compounds / Food Microbiology : Enhanced Acid Tolerance in Bifidobacterium longum by Adaptive Evolution: Comparison of the Genes between the Acid-Resistant Variant and Wild-Type Strain

( Yunyun Jiang ),( Fazheng Ren ),( Songling Liu ),( Liang Zhao ),( Huiyuan Guo ),( Caiyun Hou ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.3

Acid stress can affect the viability of probiotics, especially Bifidobacterium. This study aimed to improve the acid tolerance of Bifidobacterium longum BBMN68 using adaptive evolution. The stress response, and genomic differences of the parental strain and the variant strain were compared by acid stress. The highest acid-resistant mutant strain (BBMN68m) was isolated from more than 100 asexual lines, which were adaptive to the acid stress for 10th, 20th, 30th, 40th, and 50th repeats, respectively. The variant strain showed a significant increase in acid tolerance under conditions of pH 2.5 for 2 h (from 7.92 to 4.44 log CFU/ml) compared with the wildtype strain (WT, from 7.87 to 0 log CFU/ml). The surface of the variant strain was also smoother. Comparative whole-genome analysis showed that the galactosyl transferase D gene (cpsD, bbmn68_1012), a key gene involved in exopolysaccharide (EPS) synthesis, was altered by two nucleotides in the mutant, causing alteration in amino acids, pI (from 8.94 to 9.19), and predicted protein structure. Meanwhile, cpsD expression and EPS production were also reduced in the variant strain (p < 0.05) compared with WT, and the exogenous WT-EPS in the variant strain reduced its acid-resistant ability. These results suggested EPS was related to acid responses of BBMN68.

Lactobacillus paracasei subsp. paracasei LC01 Positively Modulates Intestinal Microflora in Healthy Young Adults

Hao Zhang,Jing Sun,Xianting Liu,Chuan Hong,Yuanbo Zhu,Aiping Liu,Siqi Li,Huiyuan Guo,Fazheng Ren 한국미생물학회 2013 The journal of microbiology Vol.51 No.6

Lactobacillus paracasei subsp. paracasei LC01 (LC01) can tolerate intestinal stresses and has antioxidant activity. To evaluate the effect of the bacterium on human intestinal microflora,a randomized, double-blind, placebo-controlled human trial was carried out. Fifty-two healthy adult volunteers were randomized equally to two groups. One group consumed 12% (wt/vol) skimmed milk supplemented with 1010 CFU of LC01 each day for the 4-week treatment period,and then consumed placebo in the next treatment period,separated by a 2-week washout. The other group followed the reverse order. Group-specific real-time PCR and biochemical analyses was used to determine the intestinal bacterial composition of fecal samples collected at the end of every period, and the concentration of short-chain fatty acids and ammonia. A significant inhibition in fecal Escherichia coli and increase in Lactobacillus, Bifidobacterium, and Roseburia intestinalis were observed after consumption of LC01. Acetic acid and butyric acid were significantly higher in the probiotic stage and fecal ammonia was significantly lower. The results indicated a modulation effect of LC01 on the intestinal microflora of young adults, suggesting a beneficial effect on bowel health. LC01 may have potential value as a probiotic.