scholarly journals Cation Dependence, pH Tolerance, and Dosage Requirement of a Bioflocculant Produced byBacillusspp. UPMB13: Flocculation Performance Optimization through Kaolin Assays

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Zufarzaana Zulkeflee ◽  
Ahmad Zaharin Aris ◽  
Zulkifli H. Shamsuddin ◽  
Mohd Kamil Yusoff
Keyword(s):  
Performance Optimization ◽  
Suspended Particle ◽  
Divalent Cations ◽  
Morphological Characteristics ◽  
Culture Broth ◽  
Ph Tolerance ◽  
Dosage Requirement ◽  
Flocculating Activity ◽  
Wide Ph Range ◽  
Ph Range

A bioflocculant-producing bacterial strain with highly mucoid and ropy colony morphological characteristics identified asBacillusspp. UPMB13 was found to be a potential bioflocculant-producing bacterium. The effect of cation dependency, pH tolerance and dosage requirement on flocculating ability of the strain was determined by flocculation assay with kaolin as the suspended particle. The flocculating activity was measured as optical density and by flocs formation. A synergistic effect was observed with the addition of monovalent and divalent cations, namely, Na+, Ca2+, and Mg2+, while Fe2+and Al3+produced inhibiting effects on flocculating activity. Divalent cations were conclusively demonstrated as the best cation source to enhance flocculation. The bioflocculant works in a wide pH range, from 4.0 to 8.0 with significantly different performances (P<0.05), respectively. It best performs at pH 5.0 and pH 6.0 with flocculating performance of above 90%. A much lower or higher pH would inhibit flocculation. Low dosage requirements were needed for both the cation and bioflocculant, with only an input of 50 mL/L for 0.1% (w/v) CaCl2and 5 mL/L for culture broth, respectively. These results are comparable to other bioflocculants produced by various microorganisms with higher dosage requirements.

scholarly journals Rapid Bacterial Recognition over a Wide pH Range by Boronic Acid-Based Ditopic Dendrimer Probes for Gram-Positive Bacteria

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 256
Author(s):  
Ayame Mikagi ◽  
Koichi Manita ◽  
Asuka Yoyasu ◽  
Yuji Tsuchido ◽  
Nobuyuki Kanzawa ◽  
...  
Keyword(s):  
Phenylboronic Acid ◽  
Pamam Dendrimer ◽  
Supramolecular Interactions ◽  
Gram Positive ◽  
Bacterial Surface ◽  
Gram Positive Bacteria ◽  
Ph Tolerance ◽  
Wide Ph Range ◽  
Ph Range ◽  
Species Specific

We have developed a convenient and selective method for the detection of Gram-positive bacteria using a ditopic poly(amidoamine) (PAMAM) dendrimer probe. The dendrimer that was modified with dipicolylamine (dpa) and phenylboronic acid groups showed selectivity toward Staphylococcus aureus. The ditopic dendrimer system had higher sensitivity and better pH tolerance than the monotopic PAMAM dendrimer probe. We also investigated the mechanisms of various ditopic PAMAM dendrimer probes and found that the selectivity toward Gram-positive bacteria was dependent on a variety of interactions. Supramolecular interactions, such as electrostatic interaction and hydrophobic interaction, per se, did not contribute to the bacterial recognition ability, nor did they improve the selectivity of the ditopic dendrimer system. In contrast, the ditopic PAMAM dendrimer probe that had a phosphate-sensing dpa group and formed a chelate with metal ions showed improved selectivity toward S. aureus. The results suggested that the targeted ditopic PAMAM dendrimer probe showed selectivity toward Gram-positive bacteria. This study is expected to contribute to the elucidation of the interaction between synthetic molecules and bacterial surface. Moreover, our novel method showed potential for the rapid and species-specific recognition of various bacteria.

Characteristics and Flocculating Mechanism of a Bioflocculant M-1 Produced by Enterobacter sp. EP3

2012 ◽  
Vol 550-553 ◽  
pp. 1482-1485 ◽  
Author(s):  
Chun Shuang Liu ◽  
Ya Dong Guo ◽  
Dong Feng Zhao
Keyword(s):  
Molar Ratio ◽  
Chemical Analyses ◽  
Infrared Spectrophotometry ◽  
Kaolin Suspension ◽  
Flocculating Activity ◽  
Wide Ph Range ◽  
Ph Range ◽  
Primary Action

A bioflocculant M-1 produced by Enterobacter sp. EP3 was investigated with regard to its flocculanting characteristics and mechanism. 2.0 mg/l M-1 showed the maximum flocculating activity of 96% in 5.0g/l Kaolin suspension containing 8mM CaCl2 and that its flocculating activity was more than 80% in a wide pH range (4.0-12.0). Chemical analyses indicated that the biopolymer M-1 was mainly a polysaccharide, mainly consist of rhamnose and glucose with a molar ratio of 9:1. Infrared spectrophotometry showed the presence of carboxyl, hydroxyl and methoxyl groups in M-1 molecular. Flocculation of Kaolin suspension with M-1 acted as a model to explore the flocculating mechanism in which bridging mediated by Ca2+ was proposed as the primary action based on the experimental observations.

Polarographic and spectrophotometric behaviour of some N-p-phenyl substituted benzamidines

1991 ◽  
Vol 56 (12) ◽  
pp. 2791-2799 ◽  
Author(s):  
Juan A. Squella ◽  
Luis J. Nuñez-Vergara ◽  
Hernan Rodríguez ◽  
Amelia Márquez ◽  
Jose M. Rodríguez-Mellado ◽  
...  
Keyword(s):  
Spectrophotometric Study ◽  
Absorption Bands ◽  
Electrochemical Parameters ◽  
Wide Ph Range ◽  
Group A ◽  
Substituent Constants ◽  
Ph Range ◽  
The Waves

Five N-p-phenyl substituted benzamidines were studied by DC and DP polarography in a wide pH range. Coulometric results show that the overall processes are four-electron reductions. Logarithmic analysis of the waves indicate that the process are irreversible. The influence of the pH on the polarographic parameters was also studied. A UV spectrophotometric study was performed in the pH range 2-13. In basic media some variations in the absorption bands were observed due to the dissociation of the amidine group. A determination of the pK values was made by deconvolution of the spectra. Correlations of both the electrochemical parameters and spectrophotometric pK values with the Hammett substituent constants were obtained.

High degradation efficiency of sulfamethazine with the dual-reaction-center Fe-Mn-SiO2 Fenton-like nanocatalyst in a wide pH range

2021 ◽  
Author(s):  
Manoj Kumar Panjwani ◽  
Qing Wang ◽  
Yueming Ma ◽  
Yuxuan Lin ◽  
Feng Xiao ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Reaction Center ◽  
Degradation Efficiency ◽  
Heterogeneous Fenton ◽  
Wide Ph Range ◽  
Ph Range

The development of a heterogeneous Fenton-like catalyst, possessing high degradation efficiency in a wide pH range, is crucial for wastewater treatment. The Fe-Mn-SiO2 catalyst was designed, and prepared by a...

scholarly journals Defect-Rich Heterogeneous MoS2/rGO/NiS Nanocomposite for Efficient pH-Universal Hydrogen Evolution

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 662 ◽  
Author(s):  
Guangsheng Liu ◽  
Kunyapat Thummavichai ◽  
Xuefeng Lv ◽  
Wenting Chen ◽  
Tingjun Lin ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
Reduced Graphene ◽  
Heterogeneous Interfaces ◽  
Wide Ph Range ◽  
Ph Range ◽  
A Current ◽  
Poor Stability

Molybdenum disulfide (MoS2) has been universally demonstrated to be an effective electrocatalytic catalyst for hydrogen evolution reaction (HER). However, the low conductivity, few active sites and poor stability of MoS2-based electrocatalysts hinder its hydrogen evolution performance in a wide pH range. The introduction of other metal phases and carbon materials can create rich interfaces and defects to enhance the activity and stability of the catalyst. Herein, a new defect-rich heterogeneous ternary nanocomposite consisted of MoS2, NiS and reduced graphene oxide (rGO) are synthesized using ultrathin αNi(OH)2 nanowires as the nickel source. The MoS2/rGO/NiS-5 of optimal formulation in 0.5 M H2SO4, 1.0 M KOH and 1.0 M PBS only requires 152, 169 and 209 mV of overpotential to achieve a current density of 10 mA cm−2 (denoted as η10), respectively. The excellent HER performance of the MoS2/rGO/NiS-5 electrocatalyst can be ascribed to the synergistic effect of abundant heterogeneous interfaces in MoS2/rGO/NiS, expanded interlayer spacings, and the addition of high conductivity graphene oxide. The method reported here can provide a new idea for catalyst with Ni-Mo heterojunction, pH-universal and inexpensive hydrogen evolution reaction electrocatalyst.

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