Isolation and selection of phenol-degrading microorganisms from industrial wastewaters and kinetics of the biodegradation

Among 22 species of microorganisms isolated from phenol-containing wastewaters, Candida parapsilopsis was found to be capable of growth on a medium with 1 g/L phenol. Kinetic parameters of phenol biodegradation in a batch reactor were determined by measuring biomass growth rates and phenol concentration as a function of fermentation time. The Haldane equation described cell growth adequately, with kinetic constants mumax = 0.174/h, KS = 11.2 mg/L and Ki = 298 mg/L.     

An enzymatic method for removal of phenol from industrial effluent

Phenols in an aqueous solution were removed after treatment with peroxidase in the presence of hydrogen peroxide. Phenols occur in wastewater of a number of industries, such as high temperature coal conversion, petroleum refining, resin and plastic, wood and dye industries, etc. It can be toxic when present at elevated levels and is known to be carcinogeneous. Thus, removal of such compound from these industrial effluents is of great importance. An enzymatic method for removal of phenols from industrial wastewater, using turnip peroxidase, has been developed. Phenol-containing industrial wastewater was treated with immobilized turnip peroxidase in the presence of hydrogen peroxide. In the reaction, a number of phenols are oxidized to form the corresponding free radicals in the presence of hydrogen peroxide as an oxidant. Free radicals polymerize to form substances that are less soluble in water than the original substances. The precipitates were removed by conventional methods and residual phenol was estimated. The present report describes the immobilization of turnip peroxidase on silica via covalent coupling, and its utility in phenol removal. A comparative study was also carried out with other immobilization techniques, viz., calcium alginate entrapment, polyacrylamide gel entrapment, etc. Peroxidase, covalently bound to silica, showed 95% removal of phenol, whereas naphthol was removed up to 99%.     

苯酚降解菌的分离及培养特性研究

对南充市郊炼油厂活性污泥进行富集,驯化筛选得到2株能以苯酚作为唯一碳源和能源生长的菌株,编号为S1,S2,两菌株可耐10,000mg/L左右的苯酚浓度,实验得出其最佳生长条件为pH7-8,温度25℃-30℃,在适宜条件下,对苯酚有较好的降解能力,而且苯对两菌株的生长表现为抑制作用。     

Isolation and selection of cellulolytic fungi from palm oil mill effluent

Cellulolytic fungi, 34 strains, were isolated from samples taken from palm oil mill residues and effluent, and high cellulase producers selected in comparison with nine known reference strains. Although 13 isolates showed good filter paper distintegration within 14 days, only eight isolates exhibited clearing zones around their colonies on carboxymethylcellulose (CMC) agar medium. Quantitative cellulase activity measurements, using CMC as carbon source, selected three of the eight isolates as potential cellulase producers. Using dried palm oil mill condensate as carbon source, only one of the isolates (F 11) showed similar results on both carbon sources. During media optimization for CMCase production, a four-fold increase from 0.058 to 0.275 U/ml was obtained using a medium, containing 0.1% (v/v) Tween 80 0.02% (w/v) NH₄NO₃, 0.025% (w/v) proteose-peptone and 0.1% (w/v) CMC dissolved in undiluted condensate from the sterilization of oil palm bunches, with an initial pH of 5.5.     

Isolation of microorganisms capable of degrading isoquinoline under aerobic conditions

Isoquinoline-degrading microbial cultures were isolated from oil- and creosote-contaminated soils. The establishment of initial enrichment cultures required the use of emulsified isoquinoline. Once growth on isoquinoline was established, isoquinoline emulsification was no longer required for utilization of isoquinoline as the sole source of carbon and nitrogen by these cultures. An isoquinoline-degrading Acinetobacter strain was isolated from one of the enrichment cultures. The degradation of isoquinoline was accompanied by the accumulation of a red cell-associated pigment and of 1-hydroxyisoquinoline, which was further degraded to unknown intermediary ring-cleavage products and carbon dioxide.     

Isolation of microorganisms capable of degrading isoquinoline under aerobic conditions.

Isoquinoline-degrading microbial cultures were isolated from oil- and creosote-contaminated soils. The establishment of initial enrichment cultures required the use of emulsified isoquinoline. Once growth on isoquinoline was established, isoquinoline emulsification was no longer required for utilization of isoquinoline as the sole source of carbon and nitrogen by these cultures. An isoquinoline-degrading Acinetobacter strain was isolated from one of the enrichment cultures. The degradation of isoquinoline was accompanied by the accumulation of a red cell-associated pigment and of 1-hydroxyisoquinoline, which was further degraded to unknown intermediary ring-cleavage products and carbon dioxide.     

Bioremediation of an industrial effluent containing monocrotophos

Almost 30% of the precious agricultural output of India is lost owing to pest infestation. In India, pesticide consumption for protecting crops is about 3% of the total world consumption. Monocrotophos (MCP), an organophosphorus insecticide, is widely used to control insects on crops. Being readily water soluble and highly toxic, its removal from wastewater generated during manufacture becomes inevitable. Bioremediation of wastewater containing MCP by Arthrobacter atrocyaneus, Bacillus megaterium, and Pseudomonas mendocina was highest at pH 8.0, but maximum reduction in Chemical Oxygen Demand (COD) was at pH 7.0. Removal of MCP and reduction in COD by B. megaterium and Ps. mendocina were highest at 35°C, while with A. atrocyaneus, it was maximum at 30°C, under aerated culture condition and inoculum density of 10⁸ cells/ml. Use of pure cultures for bioremediation of effluent containing MCP appears to be the first such attempt. Received: 26 September 2001 / Accepted: 5 February 2002     

Treatment of paper factory effluent using a phenol degrading Alcaligenes sp. under free and immobilized conditions

Treatment of the paper factory effluent was done with free and immobilized cells of a phenol degrading Alcaligenes sp. d(2). The free cells could bring a maximum of 99% reduction in phenol and 40% reduction in chemical oxygen demand (COD) after 32 and 20 h of treatment, respectively. In the case of immobilized cells, a maximum of 99% phenol reduction and 70% COD reduction was attained after 20 h of treatment under batch process. In the continuous mode of operation using packed bed reactor, the strain was able to give 99% phenol removal and 92% COD reduction in 8h of residence time The optimum flow rate was 2.5 ml/h and the half life period was 76 h. Even after the complete removal of phenol, the strain could further enhance reduction in chemical oxygen demand, which clearly indicated that in the paper factory effluent, this strain could also oxidize organic matter other than phenol.     

Genotoxic evaluation of an industrial effluent from an oil refinery using plant and animal bioassays

Polycyclic aromatic hydrocarbons (PAHs) are genotoxic chemicals commonly found in effluents from oil refineries. Bioassays using plants and cells cultures can be employed for assessing environmental safety and potential genotoxicity. In this study, the genotoxic potential of an oil refinery effluent was analyzed by means of micronucleus (MN) testing of Alium cepa, which revealed no effect after 24 h of treatment. On the other hand, primary lesions in the DNA of rat (Rattus norvegicus) hepatoma cells (HTC) were observed through comet assaying after only 2 h of exposure. On considering the capacity to detect DNA damage of a different nature and of these cells to metabolize xenobiotics, we suggest the association of the two bioassays with these cell types, plant (Allium cepa) and mammal (HTC) cells, for more accurately assessing genotoxicity in environmental samples.     

Isolation and characterization of novel atrazine-degrading microorganisms from an agricultural soil

Six previously undescribed microorganisms capable of atrazine degradation were isolated from an agricultural soil that received repeated exposures of the commonly used herbicides atrazine and acetochlor. These isolates are all Gram-positive and group with microorganisms in the genera Nocardioides and Arthrobacter, both of which contain previously described atrazine degraders. All six isolates were capable of utilizing atrazine as a sole nitrogen source when provided with glucose as a separate carbon source. Under the culture conditions used, none of the isolates could utilize atrazine as the sole carbon and nitrogen source. We used several polymerase-chain-reaction-based assays to screen for the presence of a number of atrazine-degrading genes and verified their identity through sequencing. All six isolates contain trzN and atzC, two well-characterized genes involved in the conversion of atrazine to cyanuric acid. An additional atrazine-degrading gene, atzB, was detected in one of the isolates as well, yet none appeared to contain atzA, a commonly encountered gene in atrazine impacted soils and atrazine-degrading isolates. Interestingly, the deoxyribonucleic acid sequences of trzN and atzC were all identical, implying that their presence may be the result of horizontal gene transfer among these isolates.     

Isolation of glucosinolate degrading microorganisms and their potential for reducing the glucosinolate content of rapemeal

Abstract K88ab fimbriae are filamentous protein structures at the surface of certain enterotoxigenic Escherichia coli strains. Electron microscopy analysis of K88ab fimbriae showed that these structures have different morphological appearances dependent on the medium in which cells expressing these fimbriae or in which purified fimbriae were suspended. Thin and curled structures, thin and flexible fimbriae, a wider and rigid form of the fimbriae, and, in addition, paracrystalline structures were detected. Optical diffraction analysis of the paracrystalline structures indicated a helical conformation of K88ab fimbriae.     

两株苯酚降解菌的分离及降解特性的初步研究

从南昌钢铁公司焦化污水处理厂的活性污泥中分离出64株能降解苯酚的细菌,通过耐受性试验从中筛选出2株降解活性较高的苯酚降解菌,编号为F-38和F-64。研究表明:F-38和F-64都为G—菌,苯酚浓度越高,生长延滞期越长;两株菌降解苯酚基本发生在对数期,其对苯酚降解适宜条件为温度30℃,pH值8-9,通气有利于苯酚的降解。     

Isolation of polyhydroxyalkanoate-producing bacteria from an integrated-farming pond and palm-oil mill effluent ponds

Bacterial isolates from two environments, an integrated-farming pond in the university and palm-oil mill effluent (POME) ponds at a local palm-oil-processing factory, were screened for polyhydroxyalkanoates (PHAs). Initially Sudan Black B staining was performed to detect lipid cellular inclusions. Lipid-positive isolates were then grown in a nitrogen-limiting medium containing 2% (w/v) glucose to promote accumulation of PHA before the subsequent Nile Blue A staining. The PHA extracted from positive isolates was confirmed by nuclear magnetic resonance (NMR) spectroscopy. The proportion of PHA-positive bacterial isolates was higher in the POME ponds compared to the integrated-farming pond.     

Mechanical disintegration of microorganisms in an industrial homogenizer

Disintegration of microorganisms in a continuously working industrial homogenizer has been studied. The homogenizer consists of rotating discs in a cylinder filled with glass beads. Different parameters for disintegration of baker's yeast were investigated. The disintegration process is a first-order reaction and it is influenced by the flow rate of the suspension and by the agitator speed. At a flow rate of 200 liters/hr about 85% of the yeast cells can be disrupted in a single pass through the disintegrator. This type of disintegrator can be used for disruption of cells in order to produce single-cell protein, active enzymes and other valuable cell components.     

Isolation of polyacrylamide-degrading microorganisms from soil

Two polyacrylamide-degrading bacterial strains, No. 2 and No. 11, were isolated from soil, and identified asBacillus sphaericus No. 2 andAcinetobacter sp. No. 11, respectively. Both strains grew on medium containing polyacrylamide as sole carbon and nitrogen sources.B. sphaericus No. 2 andA. sp. No. 11 reduced by 16% and 19% of the initial polyacrylamide concentration, respectively. Optimal pH and temperature in growth ofAcinetobacter sp. No. 11 were 8.0 and 37°C, respectively. After 14-day cultivation ofA. sp. No. 11, the average molecular weight of polyacrylamide has been shifted from 2.3×10⁶ to 0.5×10⁶.     

Hexavalent chromium reduction by bacterial consortia and pure strains from an alkaline industrial effluent

Aims: To characterize the bacterial consortia and isolates selected for their role in hexavalent chromium removal by adsorption and reduction. Methods and Results: Bacterial consortia from industrial wastes revealed significant Cr(VI) removal after 15 days when incubated in medium M9 at pH 6·5 and 8·0. The results suggested chromium reduction. The bacterial consortia diversity (T‐RFLP based on 16S rRNA gene) indicated a highest number of operational taxonomic units in an alkaline carbonate medium mimicking in situ conditions. However, incubations under such conditions revealed low Cr(VI) removal. Genomic libraries were obtained for the consortia exhibiting optimal Cr(VI) removal (M9 medium at pH 6·5 and 8·0). They revealed the dominance of 16S rRNA gene sequences related to the genera Pseudomonas/Stenotrophomonas or Enterobacter/Halomonas, respectively. Isolates related to Pseudomonas fluorescens and Enterobacter aerogenes were efficient in Cr(VI) reduction and adsorption to the biomass. Conclusions: Cr(VI) reduction was better at neutral pH rather than under in situ conditions (alkaline pH with carbonate). Isolated strains exhibited significant capacity for Cr(VI) reduction and adsorption. Significance and Impact of Study: Bacterial communities from chromium‐contaminated industrial wastes as well as isolates were able to remove Cr(VI). The results suggest a good potential for bioremediation of industrial wastes when optimal conditions are applied.     

Isolation of levoglucosan-assimilating microorganisms from soil and an investigation of their levoglucosan kinases

Summary The phosphorylation activities of glucose and levoglucosan (1,6-anhydro-β-d-glucopyranose, LG) were studied in 26 types of LG-assimilating microorganisms isolated from four types of soil in China. The results showed that activities of LG kinase production in most of the yeasts were lower than those of filamentous fungi, and that the highest filamentous fungal activities (0.61 U/mg protein) was approximately twice that of yeast. The filamentous fungi and yeast with highest LG kinase production activity were identified by DNA sequence analysis of 18S or 26S rRNA gene fragments respectively. The identities of them were Alternaria alternata, Eupenicillium javanicum, Aspergillus niger, Penicillium herquei, Cryptococcus laurentii, Cryptococcus flavescens, Cryptococcus luteolus and Rhodotorula aurantiaca, respectively. In addition, the LG kinases from both types of organisms were purified. The effects of temperature and pH on LG kinase activity were also studied. There was very little change in activity between pH 7 to 10 and at temperatures below 30 °C. The apparent K _m values for ATP were also similar in different microorganisms, but K _m values for LG ranged from 48 to 102 mM.     

降解芳烃微生物的多样性

芳烃是一类生物异源物质,自然微生物群落利用其对环境的适应性,对这类物质由陌生到适应,微生物群落的遗传背景发生了变化,降解芳烃的微生物呈现出多样性,本文系统介绍了降解芳烃微生物的特性,物种资源,环境适应,遗传背景及演变;介绍了各遗传型物种的功能基因数量,表达及调控方式,指明芳烃环境污染的生物修复主要取决于高效工程构造及代谢过程的控制。     

Isolation and Identification of hydrocarbon degrading bacteria from Ennore creek

The widespread problem caused due to petroleum products, is their discharge and accidental spillage in marine environment proving to be hazardous to the surroundings as well as life forms. Thus remediation of these hydrocarbons by natural decontamination process is of utmost importance. Bioremediation is a non-invasive and cost effective technique for the clean-up of these petroleum hydrocarbons. In this study we have investigated the ability of microorganisms present in the sediment sample to degrade these hydrocarbons, crude oil in particular, so that contaminated soils and water can be treated using microbes. Sediments samples were collected once in a month for a period of twelve months from area surrounding Ennore creek and screened for hydrocarbon degrading bacteria. Of the 113 crude oil degrading isolates 15 isolates were selected and cultivated in BH media with 1% crude oil as a sole carbon and energy source. 3 efficient crude oil bacterial isolates Bacillus subtilis I1, Pseudomonas aeruginosa I5 and Pseudomonas putida I8 were identified both biochemically and phylogenetically. The quantitative analysis of biodegradation is carried out gravimetrically and highest degradation rate, 55% was recorded by Pseudomonas aeruginosa I5 isolate.