Bioflocculant Produced by Klebsiella sp. MYC and Its Appli-cation in the Treatment of Oil-field Produced Water

1IntroductionWater co-produced with oil and gas recovery istermed oil-field produced water.This water is consid-ered to be of the largest volume in the waste streamfromoil and gas production processes.The volume ofproduced water can be more than10ti mes t…     

Denitrification potential evaluation of a newly indigenous aerobic denitrifier isolated from largemouth bass Micropterus salmoides culture pond

This work evaluates the application potential of a new indigenous aerobic denitrifi er, strain Pseudomonas CW-2, isolated from a largemouth bass culture pond. The rate of ammonium-N removal by strain CW-2 was approximately 97% at a DO concentration of 5.2 mg/L. Furthermore, when nitrate and ammonia coexisted, the strain gave priority to assimilating ammonia, and thereafter to denitrifi cation. Under optimal cultivation conditions, citrate and acetate were the carbon resources, C/N was 8, dissolved oxygen was 5.2 mg/L, and pH was 7; the removal rate of ammonium reached nearly 90%. The changing patterns of different bacteria in strain CW-2-treated and the control pond water were also compared. Lower levels of ammonia, nitrite, and phosphates were observed in the treated water as compared with the controls. Meanwhile, phylum-level distributions of the bacterial OTUs revealed that P roteobacteria, Bacteroidetes, Planctomycetes, and N itrospirae continuously changed their relative abundances in relation to carbon and the addition of strain CW-2; this finding implies that the conventional denitrifi cation process was weakened under the ef fects of carbon or the presence of strain CW-2. We propose that strain CW-2 is a promising organism for the removal of ammonium in intensive fish culture systems, according to our evaluations of its denitrifi cation performance.     

Regulation of water quality and growth characteristics of indoor raceway culture of <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis>

Two modes of regulating the water quality of experimental ponds in indoor raceway culture of Litopenaeus vannamei were evaluated using simple water treatment facilities. A self-made water purifying net, aeration stone, composite microbe preparation, and Ceratophyllum demersum were placed in the experimental ponds and the culture water was circulated along the raceway inside the pond using a paddle wheel aerator. In addition, the water quality in the experimental pond was improved by draining effluent from the pipeline at the bottom of ponds 7 and 8 (mode I) and exchanging the circulating water in pond 10 (mode II) with the reservoir water in pond 9 using a pump and pipeline. The water quality in the experimental ponds was similar in response to regulation using mode I or mode II. Water quality parameters in the experimental ponds were controlled within a suitable range by simple facilities during culture period without using any chemical treatments. The rich content of dissolved oxygen was maintained by the circular flow and continuous aeration of the pond water. The respective average values of the main water parameters in experimental ponds 7 and 10 in response to regulation of the water quality using modes I and II were as follows: pH 8.17 and 7.99; DO 5.16 mg/L and 5.97 mg/L; COD_Mn 18.45 and 12.61 mg/L; TAN (NH₃-N) 0.854 mg/L (0.087 mg/L) and 0.427 mg/L (0.012 mg/L); NO₂-N 0.489 mg/L and 0.337 mg/L. Moreover, the average body length and body weight of harvested shrimp of pond 7 and pond 10 were 7.56 cm and 8.99 cm, 5.10 g and 8.33 g, respectively. Furthermore, the survival rate, average biomass yield and average condition factor of the shrimp harvested were 70% and 60%, 2.54 kg/m² and 2.14 kg/m², and 0.675 g/cm and 0.927 g/cm, respectively. Linear equations describing the relationship between body length and culture time and cubic or power functions describing the relationship between body weight and body length were obtained based on evaluation of the growth data of shrimps throughout the culture period.     

不同养殖模式虾池弧菌对抗菌药物的耐药性与虾池水质评价

研究了湛江东海岛3种不同养殖模式虾池弧菌对抗菌药物的耐药性,并对虾池水域环境的水温、盐度、DO、pH、叶绿素a、DOC、无机氮、无机磷、硅酸盐、细菌总数和弧菌数量变化进行了监测和评价。结果表明,调查的三个虾池的弧菌对万古霉素产生耐药性,高位新池和传统精养池的弧菌对利福平产生耐药性,对其他抗菌药尚未形成耐性,3个虾池的弧菌对恩诺沙星和氯霉素高度敏感,传统精养池和天然虾池的弧菌对复方新诺明、庆大霉素、TMP和环丙沙星高度敏感;在水平差异上,高位新池的弧菌比传统精养池和天然虾池对12种抗菌药更具耐药性,同时多重耐药菌株在高位新池中出现,可能与虾苗来源和配合饲料中添加了抗菌药物有关。水质监测结果表明,养殖过程中,虾池水域环境逐渐富营养化,无机氮和Chla超过富营养化阈值,细菌总数增加;两个精养池的水体富营养化程度高于天然虾池;调查期间的弧菌数量在对虾发病的感染剂量阈值范围之内,尚无弧菌病害发生的潜在危险。     

不同pH和盐度下氨氮对方斑东风螺的毒性研究

在不同海水盐度和pH的条件下进行了氨氮对日龄30 d的方斑东风螺(Babylonia areolata)的急性毒性试验。结果表明:海水盐度和pH对氨氮的毒性有较大的影响,水温为29~30℃条件下,当盐度为18、23、28时,氨氮对方斑东风螺的安全浓度分别为9.39、10.401、1.97 mg/L,盐度越低氨氮毒性越强;当pH为6.5、7.5、8.5时,氨氮对方斑东风螺的安全浓度分别为18.500、14.080、10.200 mg/L,pH值越高氨氮毒性越强。     

生物采油解堵剂中产蛋白酶菌株的筛选及培养条件优化

为研究生物酶采油解堵剂中产蛋白酶菌株的初、复筛选及培养条件优化,从大庆原油样品中筛选菌种,通过水解酪素的透明圈实验及福林酚测蛋白酶酶活的方法进行菌株的初、复筛选;以蛋白酶酶活为优化指标,采用单因素实验对筛选的产蛋白酶菌株的培养基及培养条件进行优化,优化最适培养基:可溶性淀粉为15g/L,蛋白胨为20g/L,酵母膏为20g/L,NaCl为1.0g/L,CaCl2为0.02g/L,Na2HPO4为0.2g/L,NaH2PO4为0.1g/L;在初始pH为6.0、接种量为5%(体积分数)、温度为31℃、摇床转速为160r/min的条件下,培养72h后,菌株的蛋白酶酶活为551.0U/mL,为复筛选菌株的蛋白酶酶活的22.92倍,即为菌株生长繁殖及代谢的最佳条件,能够获得更高的蛋白酶酶活,有利于后续实验的进行.结果表明:菌株产蛋白酶对原油作用效果为发酵液表面张力从作用前的56.2mN/m降低到作用后的30.5mN/m,表面张力显著降低,还有降解降黏原油等效果,具有一定的研究价值.     

Isolation of a novel strain of Cyanobacterium sp. with good adaptation to extreme alkalinity and high polysaccharide yield

The use of high alkaline medium is a feasible way to provide carbon source and prevent biological contamination for the outdoor cultivation of alkaliphilic microalgae and cyanobacteria. A novel cyanobacterial strain was isolated from the open pond of a marine green alga( Picochlorum sp. SCSIO-45015, Sanya, Hainan) and identified as Cyanobacterium sp. SCSIO-45682. The effects of initial sodium bicarbonate(NaHCO_3) concentrations on the growth and biochemical composition of Cyanobacterium sp. SCSIO-45682 were investigated. The results demonstrated that Cyanobacterium sp. SCSIO-45682 had good adaptation to 16.8-g/L NaHCO_3(the same concentration of NaHCO_3 used in Zarrouk medium for Spirulina). Moreover, the yields of biomass, polysaccharide, chlorophyll a(chl a), and phycocyanin increased under high NaHCO_3 concentrations. The maximum final biomass concentration of 2.5 g/L was observed at 8.4-g/L NaHCO_3, while the highest intracellular total saccharide content of 49.2% of dry weight(DW) and exopolysaccharide(EPS) concentration of 93 mg/L were achieved at the NaHCO_3 concentration of 16.8 g/L. The crude protein content declined under high NaHCO_3 concentrations, which provide a possible explanation for the accumulation of polysaccharide. This study shows a good potential of alkaliphilic Cyanobacterium sp. SCSIO-45682 as a polysaccharide feedstock.     

Screening on DHA-producing Antarctic bacteria N- 6 and its cultural conditions

1 IntroductionPolyunsaturated fatty acids (PUFAs) have remained as a natural product due to thesynthetic difficulty of reproducing the methylene interrupted double bond sequence by in-dustrial chemistry. Their significance to animals and humans lies in th…     

对虾育苗用水综合处理技术

用物理、化学、生物和药物等方法综合系统地处理对虾育苗用水:1)澄清海水,用10~20 mg/L生石灰调节酸碱度;2)在沉淀海水中泼洒沸石粉30～50 mg/L,去除或降低总氨氮、亚硝酸氮等有害物质;3)用15~23 mL/m3甲醛消毒海水,杀除海水病原体;4)用棉花、过滤袋双层过滤,减少微细悬浮物及有害生物;5)育苗池投放水质改良剂及有益微生物制剂,维持稳定良好的水质,确保幼体正常生长。结果:对虾出苗率提高30%～100%。     

The hydrochemical features of salt lakes in Qaidam Basin

There are 37 lakes in the Qaidam Basin: 1 freshwater lake, 6 brackish-water lakes, 2 saline-water lakes and 28 salt lakes. The pH value of salt lake brines is 7.014 on the average, and the average total mineralization is 340.75 g/1. Their water bodies belong mainly to the five-component equilibrium system,: Na, K, Mg//SO₄, Cl-H₂O, which can be further grouped into sodium-magnesium sulfate subtype, magnesium sulfate subtype, chloride transition subtype and chloride type water by their hydrochemical property. The salt lake brines of the first salt forming epoch (N₂−Q₃) were of the sulfate type. In the second salt forming epoch (Q₃−Q₄), some of them were of the chloride type. The pH value of brines decreases with the increase of total mineralization. The pH value is lower when the total mineralization is from 50–310 g/l and higher when the total mineralization is from 310–355 g/l, however, when the total mineralization is higher than 355 g/l, the pH value decreases slowly again. The total mineralization of the chloride type and the chloride transition subtype brine is higher than the sulfate type, being 310–530 g/l, 310–470 g/l, and less than 355 g/l in that order. Of the 40 chemical compositions in the saline lake brines in Qaidam Basin, potassium is mainly concentrated in the chloride type and chloride transition subtype brine, boron and lithium mainly in the sulfate type. Evaporation experiments show that boron and lithium are accumulated in concentrated brine until crystallization of bischofite takes place. Potassium is also accumulated in concentrated brine during the salt forming stage, but its concentration decreases with the increase of total mineralization during the potassium forming stage. This paper was published in Chinese inOcean. et Limn. Sinica;15 (4):341–359, 1984.     

凡纳滨对虾与金钱鱼混养模式水质理化因子及浮游生物群落结构的变化

以凡纳滨对虾(Litopenaeus vannamei)与金钱鱼(Scatophagus argus)混养池塘和凡纳滨对虾单养池塘为研究对象,对两池塘水体的理化因子及浮游生物进行测定。结果显示:混养池塘水体的溶解氧与单养池塘相比均无显著性差异;混养和单养池塘的化学需氧量(COD)、亚硝酸盐和氨氮的含量在实验过程中均呈现持续上升趋势,但混养池上升趋势较缓,两池塘的上述指标在养殖前期差异不显著,养殖后期有显著差异(P<0.05)。在养殖后期,混养池塘的浮游植物丰度显著大于单养池塘(P<0.05),而浮游动物丰度显著低于单养池塘(P<0.05)。结果表明,混养金钱鱼可有效改善凡纳滨对虾精养池塘的水质,降低亚硝酸盐、氨氮及COD的含量,稳定浮游植物种群结构,控制池塘中浮游动物的过度繁殖。     

Production of polyhydroxybutyrate by the marine photosynthetic bacterium Rhodovulum sulfidophilum P5

The effects of different NaCl concentrations, nitrogen sources, carbon sources, and carbon to nitrogen molar ratios on biomass accumulation and polyhydroxybutyrate (PHB) production were studied in batch cultures of the marine photosynthetic bacterium Rhodovulum sulfidophilum P5 under aerobic-dark conditions. The results show that the accumulation of PHB in strain P5 is a growth-associated process. Strain P5 had maximum biomass and PHB accumulation at 2%-3% NaCl, suggesting that the bacterium can maintain growth and potentially produce PHB at natural seawater salinity. In the nitrogen source test, the maximum biomass accumulation (8.10±0.09 g/L) and PHB production (1.11±0.13 g/L and 14.62%±2.25% of the cell dry weight) were observed when peptone and ammonium chloride were used as the sole nitrogen source. NH 4 + -N was better for PHB production than other nitrogen sources. In the carbon source test, the maximum biomass concentration (7.65±0.05 g/L) was obtained with malic acid as the sole carbon source, whereas the maximum yield of PHB (5.03±0.18 g/L and 66.93%±1.69% of the cell dry weight) was obtained with sodium pyruvate as the sole carbon source. In the carbon to nitrogen ratios test, sodium pyruvate and ammonium chloride were selected as the carbon and nitrogen sources, respectively. The best carbon to nitrogen molar ratio for biomass accumulation (8.77±0.58 g/L) and PHB production (6.07±0.25 g/L and 69.25%±2.05% of the cell dry weight) was 25. The results provide valuable data on the production of PHB by R. sulfidophilum P5 and further studies are on-going for best cell growth and PHB yield.     

Isolation and characterization of a marine bacterium producing protease from Chukchi Sea, Arctic

A Gram negative bacterium Ar/W/b/75°25＇N/1 producing extracellular alkaline protease was isolated from surface water of latitude 75°25＇N, and longitude 162°25＇W in Chukchi sea, Arctic. The strain can grow at the temperature range from 7℃ to 30℃, and grow better at 30(℃. It can not grow at 40℃. Keeping certain salinity concentration in medium is necessary for cell growth. It grows well in medium containing salinity concentration from 0. 5 % to 10 % sodium chloride. Glucose, sucrose and soluble starch can be utilized by the strain, among which glucose is the optimal carbon source. Peptone is the optimal organic nitrogen source for cell growth and protease producing, and ammonium nitrate is the optimal inorganic nitrogen source.About 75.7% of total protease of the strain are extracellular enzyme. Optimal temperature for proteolytic activity is at 40℃. Protease of the strain keeps stable below 40℃, and shows high proteolytic activity within the pH range from 7 to 11.     

波纹龙虾胚胎对五种生态因子的适应性

【目的】研究波纹龙虾(Panulirus homarus)胚胎对生态因子的耐受能力,为龙虾繁殖提供数据。【方法】采用封闭静水实验方法和常规生物急性毒性实验法。在温度(30±0.5)℃,盐度30,pH(8.10±0.1)和溶解氧(DO)为(5.0±0.5)mg/L条件下,分别进行温度、盐度、pH的骤变和渐变对波纹龙虾胚胎存活影响研究;根据急性毒性预实验结果设置等对数间距浓度值,进行氨氮和亚硝酸盐氮对波纹龙虾胚胎的急性毒性实验。【结果与结论】波纹龙虾胚胎发育的温度、盐度和pH耐受范围分别为7~36℃、15~45和5.8~9.4;波纹龙虾胚胎适宜温度为15~30℃,适宜盐度为30~35,适宜pH为7.0~8.5;氨氮和亚硝酸盐氮毒性效应与浓度和暴露时间呈正相关。氨氮和亚硝酸盐氮暴露24~96 h,波纹龙虾胚胎存活率组间存在显著性差异(P<0.05)。氨氮对波纹龙虾胚胎24、48、72和96 h的半致死浓度(LC₅₀)分别是180.46、61.11、41.87、26.58 mg/L,安全浓度(SC)为2.66 mg/L;亚硝酸盐氮对波纹龙虾胚胎24、48、72和96 h的LC₅₀分别是839.50、423.75、214.48、135.41 mg/L,SC为13.54 mg/L。     

A comparative analysis of fatty acid composition and fucoxanthin content in six <Emphasis Type="Italic">Phaeodactylum tricornutum</Emphasis> strains from diff erent origins

Phaeodactylum tricornutum is a potential livestock for the combined production of eicosapentaenoic acid (EPA) and fucoxanthin. In this study, six marine diatom strains identified as P. tricornutum were cultured and their total lipid, fatty acid composition and major photosynthetic pigments determined. It was found that the cell dry weight concentration and mean growth rate ranged between 0.24–0.36 g/L and 0.31–0.33/d, respectively. Among the strains, SCSIO771 presented the highest total lipid content, followed by SCSIO828, and the prominent fatty acids in all strains were C16:0, C16:1, C18:1, and C20:5 (EPA). Polyunsaturated fatty acids, including C16:2, C18:2, and EPA, comprised a significant proportion of the total fatty acids. EPA was markedly high in all strains, with the highest in SCSIO828 at 25.65% of total fatty acids. Fucoxanthin was the most abundant pigment in all strains, with the highest in SCSIO828 as well, at 5.50 mg/g. The collective results suggested that strain SCSIO828 could be considered a good candidate for the concurrent production of EPA and fucoxanthin.     

亚硝酸氮对红鳍东方[鱼屯]的毒性效应

采用半静水生物测试法,研究亚硝酸盐氮对红鳍东方[鱼屯]（Takifugu rubripes）（95～9．8g）的急性毒性及对部分肝脏抗氧化酶活性的影响。结果表明,在急性毒性实验中,亚硝酸盐氮对红鳍东方[鱼屯]的24、48、72和96h半致死质量浓度（LC50）分别为20188、19057、17109、15925mg／L,安全质量浓度为1592mg／L;在亚急性毒性实验中,当红鳍东方纯分别在5．3、106,159、212mg／L亚硝酸盐氮中暴露4周时,其肝脏总抗氧化能力（T—AOC）、超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性随亚硝酸盐氮浓度的升高均被显著抑制,差异有统计学意义（P〈0.05）,表明亚硝酸盐氮会对鱼体的抗氧化能力产生影响。     

Effects of culture conditions on growth and docosahexaenoic acid production from Schizochytrium limacinum

The effects of temperature, initial pH, salinity of culture medium, and carbon and nitrogen sources on growth and docosahexaenoic acid （C22：6 n-3, DHA） production from Schizochytrium limacinum OUC88 were investigated in the present study. The results revealed that the optimal temperature, initial pH and salinity level of the medium for DHA production were 23 ℃, 7.0 and 18, respectively. Glucose was proved the best carbon source for the growth and DHA production from S. limacinum. Among the nitrogen sources tested, soybean cake hydrolysate, a cheap by-product, was found to be effective for the accumulation of DHA in S. limacinum cells. In addition, increasing the concentration of carbon sources in the medium caused a significant increase in cell biomass; however, accumulation of DHA in cells was mainly stimulated by the ratio of C/N in the medium. Under the optimal culture conditions, the maximum DHA yield achieved in flasks was 4.08 g L^-1 after 5 d of cultivation     

The selection of alkaline protease-producing yeasts fi＇om marine environments and evaluation of their bioactive peptide production

A total of 400 yeast strains from seawater, sediments, saltern mud, marine fish guts, and marine algae were obtained. The protease activity of the yeast cultures was estimated, after which four strains (HN3.11, N11b, YF04C and HN4.9) capable of secreting extracellular alkaline protease were isolated. The isolated strains were identified as Aureobasidium pullulans, Yarrowia lipolytica, Issatchenkia orientalis and Cryptococcus cf. aureus. The optimal pH of the protease activity produced by strains HN3.11, YF04C, and HN4.9 was 9.0, while that of the protease produced by strain N11b was 10.0. The optimal temperature for protease activity was 45°C for strains HN3.11, N11b, and YF04C, and 50°C for strain HN4.9. After digestion of shrimp (Penaeus vannamei) protein and spirulina (Arthospira platensis) protein with the four crude alkaline proteases, the filtrate from spirulina (Arthrospira platensis) powder digested by the crude alkaline protease of strain HN3.11 was found to have the highest antioxidant activity (61.4%) and the highest angiotensin I converting enzyme (ACE)-inhibitory activities (68.4%). The other filtrates had much lower antioxidant activity and ACE-inhibitory activities.     

Isolation and characterization of venom from nematocysts of jellyfish Rhopilema esculentum Kishinouye

The present work is the first report of the biochemical characterization of the venom from nematocysts of the jellyfish Rhopilema esculentum Kishinouye. The nematocysts were isolated by autolysis and centrifugation and separated by flow cytometry. Four types of nematocysts were identified: mastigophores, euryteles, and atrichous and holotrichous isorhiza. SDS-PAGE and amino acid analyses demonstrated that most of the proteins in the nematocyst extract were between 10 kDa and 40 kDa, and that glutamic acid was the main amino acid. A hemolytic activity assay showed that the activity of the nematocyst venom (RNV) was strongest in Tris-HCl buffer (50 mmol/L, pH 7.8, 5% glycerol, 0.5 mmol/L EDTA, 0.1 mol/L NaCl). The hemolytic activity was related to protein concentration and the HU50 against chicken erythrocytes was 0.91 μg/mL.     

凡纳滨对虾高位池养殖系统的水质理化状况

对凡纳滨对虾高位养殖池水质环境状况进行了研究。结果表明,养殖期间虾池水体透明度前期较高,中后期较低;虾池pH变化在7.89~9.02之间,变化幅度较小。虾池水体悬浮物数量和CODMn随养殖时间延长而持续升高,变化范围分别为18.5~162.3 mg/L和3.52~14.58 mg/L。虾池水体中营养盐各月份波动较大,无机氮的数量变化在0.206~1.621 mg/L之间,含量逐渐升高,磷酸盐数量变化在0.009~0.067 mg/L之间,含量逐渐下降。水环境中N、P比较高,平均为62.7。养殖水体中后期处于严重富营养化状态。