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.     

降解烤烟秸秆和烟碱菌株的筛选及其产酶特性

摘要:【目的】为获得能够降解烤烟秸秆和烟碱的菌株,并探索其降解烤烟秸秆的利用途径。【方法】以烤烟秸秆为唯一碳氮源,从烟田土壤中进行了菌株的筛选。采用形态学观察、生理生化特性鉴定、16S rRNA基因序列鉴定等方法对该菌株进行了鉴定,并对其以烤烟秸秆为底物进行液态发酵的产酶活性和木质纤维素降解效果进行了测定。【结果】结果表明:该菌株为巨大芽孢杆菌(Bacillus megaterium)。在以烤烟秸秆为主要营养物质液态发酵条件下该菌株具有较强的木质素降解能力,最大漆酶活力达到418.52 U/L,而木质素过氧化物酶和锰过氧化物酶的最大酶活分别为19.71 U/L 和64.71 U/L。此外,发酵20 d后该菌能够完全降解发酵液中的烟碱。【结论】本研究筛选到了1株能够较好降解烤烟秸秆和完全降解烟碱的巨大芽孢杆菌(Bacillus megaterium),且该菌株具有利用烤烟秸秆生产漆酶的应用价值。     

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.     

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.     

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     

Selection of vinasse degrading microorganisms

Vinasse is a highly colored effluent with a high pollutant potential when disposed in the environment. Assays for decolorization of vinasse were performed, selecting the fungus Pleurotus sajor-caju CCB 020. The discoloration was cocominant with the increase of the activities of laccase, manganese-peroxidase and peroxidases. P. sajor-caju demonstrated a rise in biomass production (1.06 g 100 ml⁻¹), and the enzyme activities such as laccase (varying from 400 to 450 IU l⁻¹) reached between the 9th and 10th day of growth and for MnP at the 12th day of cultivation (varying from 60 to 100 IU l⁻¹). It was concluded that the system P. sajor-caju/vinasse can be utilized as a bioprocess for color removal and degradation of complex vinasse compounds. It was observed an improvement in the characteristics and detoxification allowing its utilization as reused water, laccase and manganese-peroxidase enzymes production and for fungal biomass production with a high nutritional value.     

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 and characterization of a furfural degrading sulfate-reducing bacterium from an anaerobic digester

A sulfate-reducing bacterium (SRB) was isolated from a continuous anaerobic digester, which converted the furfural-containing wastewater to methane and CO₂. This SRB isolate could use furfural, furfuryl alcohol, and 2-furoic acid as sole source of carbon and energy in a defined mineral sulfate medium. Acetic acid was the major end product of furfural degradation. This organism also used wide varieties of other carbon sources, including ethanol, pyruvate, lactate, succinate, propanol, formate, and malate. The SRB isolate contained the electron carrier desulfoviridin. It used SO₄, NO₃, and thiosulfate as electron acceptors. This isolate used ammonium chloride, nitrate and glutamate as nitrogen source. The characteristics of the SRB isolate were closely similar toDesulfovibrio sp.     

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.     

聚乳酸降解菌株筛选鉴定及降解过程优化

【目的】筛选能够降解聚乳酸的微生物, 提高聚乳酸的降解速率并鉴定聚乳酸降解酶种类。【方法】以明胶为唯一碳源, 筛选能够降解聚乳酸的微生物; 通过优化明胶添加浓度、聚乳酸添加量以及金属离子种类提高聚乳酸的降解速率; 通过分析降解过程中代谢产物和酶活力变化明确聚乳酸降解酶类别。【结果】筛选获得一株聚乳酸降解菌株, 鉴定为Lentzea waywayandensis; 经优化培养, 聚乳酸在25 d后失重84.8%; 降解过程中, 检测到乳酸的产生, 体外酶活实验仅检测到蛋白酶活力。【结论】明胶作为唯一碳源适用于聚乳酸降解菌株的筛选; 明胶作为碳源的同时可以作为诱导剂诱导菌株L. waywayandensis降解聚乳酸; 此外, 研究表明蛋白酶在聚乳酸降解过程中发挥重要作用。     

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.