ABSTRACT
Lead is one of the four heavy metals that has a profound damaging effects on human health. In the recent past there has been an increasing global concern for development of sustainable bioremediation technologies for detoxification of lead contaminant. Present investigation highlights for lead biosorption by a newly isolated novel bacterial species; Achromobacter sp. TL-3 strain, isolated from activated sludge samples contaminated with heavy metals (collected from oil refinery, Assam, North-East India). For isolation of lead tolerant bacteria, sludge samples were enriched into Luria Broth medium supplemented separately with a range of lead nitrate; 250, 500, 750, 1000, 1250 and 1500 ppm respectively. The bacterial consortium that could tolerate 1500 ppm of lead nitrate was selected further for purification of lead tolerant bacterial isolates. Purified lead tolerant bacterial isolates were then eventually inoculated into production medium supplemented with ethanol and glycerol as carbon and energy source to investigate for bioflocculant production. Bioflocculant production was estimated by monitoring the potential of lead tolerant bacterial isolate to flocculate Kaolin clay in presence of 1% CaCl2. Compared to other isolates, TL-3 isolate demonstrated for maximum bioflocculant activity of 95% and thus was identified based on 16S rRNA gene sequence analysis. TL3 isolate revealed maximum homology (98%) with Achromobacter sp. and thus designated as Achromobacter sp. TL-3. Bioflocculant activity of TL-3 isolate was correlated with the change in pH and growth. Achromobacter sp. TL-3 has significant potential for lead biosorption and can be effectively employed for detoxification of lead contaminated waste effluents/waste waters.
Subject(s)
Achromobacter/classification , Achromobacter/drug effects , Achromobacter/isolation & purification , Adaptation, Physiological , Base Sequence , Culture Media , DNA Primers , Flocculation , Lead/toxicity , Molecular Sequence Data , Phylogeny , Sewage , Spectrophotometry, AtomicABSTRACT
In this study, a bioflocculant with a high flocculation activity (>98%) produced by strain 40B, which was isolated from a brackish water was investigated. By 16S rDNA sequence analysis, strain 40B was identified as Bacillus velezensis. Chemical analysis of the bioflocculant 40B indicated that it contained 2% protein and 98% carbohydrates. FTIR analysis showed the presence of carboxyl, hydroxyl and amino groups, which were preferred for the flocculation process. The optimal concentration for the flocculation activity was 3.5 mg l-1. This polysaccharide could also flocculate kaolin suspension over a wide range of pH (1–10) and temperature (5–85 °C) in the presence of CaCl2. The stability of the bioflocculant 40B under various conditions suggests its possible use in the industries and environmental applications. However, no previous report exists on the isolation and characterization of a bioflocculant from the Bacillus velezensis.
ABSTRACT
Normal bacteria purification method was used in this study. Pseudomonas trivialis and Neurospora te-trasperma were screened from residues of traditional Chinese medicine (TCM). The fermentation conditions and flocculating function were also studied. The results showed that the selected strains grow well in the residues of TCM and their products can flocculate kaolin suspension solution. Based on these, we explored effects of various factors on the flocculated results in order to reveal the best fermentation condition among different combinations.
ABSTRACT
Objective To screen the flocculatnt-producing strain from activated sludge that can treat azo dyeing wastewater effectively.Methods Screening and rescreening were used to acquire the strain which possesses high efficiency of flocculatant production and the strain was identified.The character of microbial flocculant(MBF) and the ability to treat azo dye wastewater were studied.Results A strain of high-efficiency bioflocculant-producting bacteria(AJ-6),initially identified as Alcaligenes sp,was screened.The bioflocculant produced by the strain was able to flocculate kaolin suspension with 94.4% and fly ash suspension with 98.9% respectively.The flocculation activity distribution tests showed that the active components of the bioflocculant existed in the supernatant fluid after centrifugation.It had good treatment efficiency in treating azo dyes methyl orange wastewater.The maximal efficiencies of removing CODCr and chroma from the wastewater were 81.3% and 94.2%.Compared with the other flocculants,the performance of MBF was better than that of polyacrylamide(PAM),aluminum sulfate,ferrous sulfate.The MBF was more thermostable when treated with 100 ℃ for 30 min,and the animal toxicity test showed that the MBF had no acute toxicity to mice.Conclusion The bioflocculant produced by the strain AJ-6 is applicable to treat azo dyeing wastewater and can be also used for the other wastewater.
ABSTRACT
strain 49 #(BD-4),which had the highest flocculating activity among 752 strains,was picked out.The fermentation condi tions and the flocculating influence factors were studied.By testing,this cult ure broth had a much more ability to get rid of suspended materials in water and to decolourize the high-density dyestuff wastewater. In laboratory scale,bioflocculant was roughly extracted from culture broth by t he technological process,water extraction-organic solvent sediment-vacuum dry .The suitable work conditions of each step were set up through the tests.0 198 5g dry product was obtained from 100mL culture broth.
ABSTRACT
The conditions of Pseudomonas sp.GX 4\|1 producing flocculant only using fish meal wastewater were mainly studied.Under the optimum culture conditions:medium COD 10g/L,initial pH 7～9,cultural temperature 30,and the shaking speed,100～250r/min,the flocculating rates can highly reach more than 97% with maxmium 99 5%,even if the culture medium was not sterilized.This flocculant shows high flocculating efficiency to kaolin clay suspension,soil suspension,activate carbon powder suspension and wastewater fromelectroceramics plant.
ABSTRACT
A strain of high-efficiency bioflocculant-producting bacteria,which was named TJ-3,was screened from sewage sludge.The strain was gram-negative and rod-shaped in physiological biochemical test and was identified as Pseudomonas aeruginosa by 16S rDNA Sequencing.According to the growth curve of the TJ-3 strain,the growth stabilization period is long so that Microbial Flocculants(MBF) production is stable.The MBF produced by the TJ-3 strain is able to flocculante kaolin suspension with 98.2%.The MBF activity distribution tests show that most of the active components of the bioflocculant exist in deposition after centrifufation.When pH is 8.5,1%(quality fraction) CaCl2 Solution dosing quantity is 3.5 mL,bioflocculant dosing quantity is 1.5 mL in 100 mL kaolin suspension,the bioflocculant has an optimal flocculation.