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1.
The marine yeast strain N13d, producing an extracellular amylase, was isolated from the deep sea sediments of the Pacific Ocean. This strain was identified to be Aureobasidium pullulans by 18S rRNA gene sequence analysis and routine yeast identification methods. The optimal sea water medium for amylase production by this yeast strain was 1.0% peptone and 1.0% soluble starch with pH 4.0. The optimal conditions for amylase production by this yeast strain were with temperature 28 °C, aeration rate 6 Lmin−1 and agitation speed 250 rmin−1. Under these conditions, 58.5 units of amylase activity per mg protein were produced within 56 h of fermentation.  相似文献   

2.
The marine yeast strain W6b isolated from sediment of the South China Sea was found to produce a cell-bound acid protease. The crude acid protease produced by this marine yeast showed the highest activity at pH 3.5 and 40 °C. The optimal pH and temperature for the crude acid protease were in agreement with those for acid protease produced by the terrestrial yeasts. The optimal medium of the acid protease production was seawater containing 1.0% glucose, 1.5% casein, and 0.5% yeast extract, and the optimal cultivation conditions of the acid protease production were pH 4.0, a temperature of 25 °C and a shaking speed of 140 rmin−1. Under the optimal conditions, 72.5 UmL−1 of acid protease activity could be obtained in cell suspension within 48 h of fermentation at shake flask level. The acid protease production was induced by high-molecular-weight nitrogen sources and repressed by low-molecular-weight nitrogen sources. Skimmed-milk-clotting test showed that the crude acid protease from the cell suspension of the yeast W6b had high skimmed milk coagulability. The acid protease produced by M. reukaufii W6b may have highly potential applications in cheese, food and fermentation industries.  相似文献   

3.
研究分离自对虾养殖池的一株促藻生长细菌的最佳培养条件,通过单因子实验得到该菌株的最佳碳源为葡萄糖,最佳氮源为酵母膏,初始pH值为7.5,最佳氯化钠质量浓度5 g/L;在其他培养条件不变的情况下,通过对酵母膏、葡萄糖、初始pH值做三因子三水平的正交实验,得到培养基最佳组合为:酵母膏10 g/L,葡萄糖1 g/L,初始pH值7.5。  相似文献   

4.
1 Introduction In recent years, carotenoids have received increasing attention as they have extensive use in medicine, cosmetic, chemistry, food industry and feed industry. In industry, carotenoid and astaxanthin can be used as the additives of food or feeds. Carotenoids can also serve as the precursor of vitamin A in mammals. In recent years, many types of carotenoid have aroused extensive interest because of their many beneficial effects on human health. For in-stance, lycopene and astaxant…  相似文献   

5.
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.  相似文献   

6.
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…  相似文献   

7.
Seventy-nine strains of bioflocculant-producing bacteria were isolated from 3 activated sludge samples. Among them, strain MYC was found to have the highest and stable flocculating rate for both kaolin clay suspension and oil-field produced water. The bacterial strain was identified as Klebsiella sp. MYC according to its morphological and biochemical characteristics and 16SrDNA sequence. The optimal medium for bioflocculant production by this bacterial strain was composed of cane sugar 20 g L^-1, KH2PO4 2 g L^-1, K2HPO4 5 g L^- 1, （ NH4）2SO4 0.2 g L^-1, urea 0.5 g L^- 1 and yeast extract 0.5 g L^- 1, the initial pH being 5.5. When the suspension of kaolin clay was treated with0.5% of Klebsiella sp. MYC culture broth, the flocculating rate reached more than 90.0% in the presence of 500mg L^-1 CaCI2, while the flocculating rate for oil-field produced water was near 80.0% in a pH range of 7.0 - 9.0 with the separation of oil and suspended particles from the oil-field produced water under similar conditions. The environment-friendly nature of the bioflocculant and high flocculating rate of the strain make the bioflocculant produced by Klebsiella sp. MYC an attractive bioflocculant in oil-field produced water treatment.  相似文献   

8.
Yeast strain 10 with high yield of protease was isolated from sediments of saltern near Qingdao, China. The protease had the highest activity at pH 9.0 and 45℃. The optimal medium for the maximum alkaline protease production of strain 10 was 2.5 g soluble starch and 2.0 g NaNO3 in 100 mL seawater with initial pH6.0. The optimal cultivation conditions for the maximum protease production were temperature 24.5 ℃, aeration rate 8.0 L min^- 1 and agitation speed 150 r min^-1 . Under the optimal conditions, 623.1 Umg^-1 protein of alkaline protease was reached in the culture within 30 h of fermentation.  相似文献   

9.
After a serial of UV, EMS and NTG mutagenesis, a mutant named MM of the red marine yeast strain Rhodotorula sp. hidai was obtained. The mutant MM could produce 603.93 μg g−1 of carotenoid within 5 days in the medium containing 4.0 g sucrose, 1.5 g yeast extract, 0.1 g MgSO4, and 100 mL of sea water, with pH 6.0 and at 30 °C, while only 213.18 μg g−1 of carotenoid was produced by the wild type under the same conditions.  相似文献   

10.
Harmful algal blooms (HABs) have led to extensive ecological and environmental issues and huge economic losses. Various HAB control techniques have been developed, and biological methods have been paid more attention. Algicidal bacteria is a general designation for bacteria which inhibit algal growth in a direct or indirect manner, and kill or damage the algal cells. A metabolite which is strongly toxic to the dinoflagellate Alexandrium tamarense was produced by strain DH46 of the alga-lysing bacterium Alteromonas sp. The culture conditions were optimized using a single-factor test method. Factors including carbon source, nitrogen source, temperature, initial pH value, rotational speed and salinity were studied. The results showed that the cultivation of the bacteria at 28°C and 180 r min?1 with initial pH 7 and 30 salt contcentration favored both the cell growth and the lysing effect of strain DH46. The optimal medium composition for strain DH46 was determined by means of uniform design experimentation, and the most important components influencing the cell density were tryptone, yeast extract, soluble starch, NaNO3 and MgSO4. When the following culture medium was used (tryptone 14.0g, yeast extract 1.63g, soluble starch 5.0 g, NaNO3 1.6 g, MgSO4 2.3 g in 1L), the largest bacterial dry weight (7.36 g L?1) was obtained, which was an enhancement of 107% compared to the initial medium; and the algal lysis rate was as high as 98.4% which increased nearly 10% after optimization.  相似文献   

11.
Arctic sea ice in the polar region provides a cold habitat for microbial community. Arctic sea ice microorganisms are revealed to be of considerable importance in basic research and potential in biotechnological application. This paper investigated the culture condition and extraceIlular hydrolase of 14 strains of different Arctic sea ice bacteria. The results showed that optimal growth temperature of strains is 15 ℃ or 20 ℃. The optimal pH is about 8.0. They hardly grow at acid condition. 3 % NaCl is necessary for better growth. These strains have different abilities in producing amylase, protease, eellulase and lipase. Pseudoalteronomas sp. Bsi429 and Pseudoalteronomas sp. Bsi539 produced both cellulose, protease and lipase. These results provide a basis for further developing and exploiting the cold adapted marine enzyme resources.  相似文献   

12.
Carbohydrases secreted by marine Vibrio sp. YKW-34 with strong Laminaria cell wall degrading ability were screened, and among them alginate lyase was found to be dominant. The effects of medium composition and culturing condition on the production of alginate lyase by marine Vibrio sp. YKW-34 in flask were investigated in this study. In the culture medium of marine broth, no alginate lyase was produced. The activity of the alginate lyase, after being induced, reached 5 UmL^-1. The best inoculum volume and inoculum age were 10% and 12h, respectively. The optimal temperature for alginate lyase production was 25℃. The fermentation medium was composed of 0.5% of Laminaria powder and 0.2% of KNO3 with an initial acidity of pH 8.0. Alginate could induce alginate lyase production but not as efficiently as Laminaria powder did. The addition of fucoidan, cellulose and glucose had negative effect on the alginate lyase production. Other kinds of nitrogen sources, such as yeast extract, beef extract and peptone, had positive effect on the growth of the microorganism and negative effect on alginate lyase production. In addition, the time course of alginate lyase production under the optimized condition was described. The optimal harvest time was 48 h.  相似文献   

13.
米曲霉产中性蛋白酶的适宜条件   总被引：3，自引：0，他引：3  
研究了米曲霉产蛋白酶的分布,优化了米曲霉产中性蛋白酶的适宜培养条件以及培养基的最优组成。研究发现米曲霉产中性蛋白酶的能力为最强。米曲霉产中性蛋白酶的适宜培养条件为:m(麸皮)∶m(豆粕粉)=4∶1,水的质量分数为60%,培养基中各无机盐质量分数为:KNO30.2%,MgSO40.05%,Na2HPO40.13%,pH值为6.0,接种量为每10 g培养基接种1.0×108个孢子,最佳培养温度为30℃,最佳培养时间为48 h。在此培养条件下,最高酶活力达3 999.2 U.g-1。  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
Microorganisms living in polar zones play an important part as the potential source of organic activity materials with low temperature characteristics in the bio-technological applications. A psychrotrophic bacterium (strain Ar/w/b/75°/10/5) , producing cellulose at low temperatures during late-exponential and early-stationary phases of cell growth, was isolated from sea ice-covered surface water in Chuckchi Sea, Arctic. This bacterium, with rod cells, was Gram-negative, slightly halophilic. Colony growing on agar plate was in black. Optimum growth temperature was 15℃. No cell growth was observed at 351 or above. Optimum salt concentration for cell growth was between 2 and 3 % of sodium chloride in media. Maximal cellulase activity was detected at a temperature of 35℃ and pH8. Cellulase was irreversibly inactivated when incubated at 55℃ within 30 min. Enzyme can be kept stable at the temperature no higher than 25℃. Of special interest was that this bacterium produced various extracellular enzymes i  相似文献   

17.
Totally more than 500 yeast strains were isolated from seawater, sea sediments, mud of sea salterns, marine fish guts and marine algae. The results of routine and molecular biology identification methods show that nine strains among these marine yeasts belong to Aureobasidium pullulans, although the morphologies of their colonies are very different. The marine yeasts isolated from different marine environments indicate that A. pullulans is widely distributed in different environmental conditions. These Aureobasidium pullulans strains include A. pullulans 4#2, A. pullulans N13d, A. pullulans HN3-11, A. pullulans HN2-3, A. pullulans JHSc,A. pullulans HN4.7, A. pullulans HN5.3, A. pullulans HN6.2 and A. pullulans W13a. A. pullulans 4#2 could produce cellulase and single cell protein. A. pullulans N13d could produce protease, lipase, amylase and cellulase. Both A. pullulans HN3-11 and A. pullulans HN2-3 were able to produce protease, lipase and cellulase. A. pullulans JHSc could secrete cellulase and killer toxin. Both A.pullulans HN4.7 and A. pullulans HN5.3 could yield lipase and cellulase. A. pullulans W13a was able to secrete extracellular amylase and cellulase while A. pullulans HN4.7 and A. pullulans N13d could produce siderophores. This means that different A. pullulans strains from different marine environments have different physiological characteristics, which may be applied in many different biotechnological industries.  相似文献   

18.
A psychrophilic bacterium strain 547 producing cold-adaptive alkaline protease was isolated from the deep sea sediment of Prydz Bay, Antarctica. The organism was identified as a Planomicrobium species by 16S rRNA analysis. The optimal and highest growth temperatures for strain 547 were 15℃ and 30℃, respectively. The extracellular protease was purified by ammonium sulfate precipitation and DEAE cellulose-52 chromatography. The optimal temperature and pH for the activity of the purified enzyme were 35 ℃ and pH 9.0, respectively. The enzyme retained approximately 40% of its activity after 2 h of incubation at 50℃. The enzymatic activity was inhibited by 1 mmol/L phenylmethyl sulfonylfluoride (PMSF) and hydrochloride 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF), indicating that it was a serine protease. The presence of Ca2+ and Mn2+ increased the activity of the enzyme. The protease gene with a size of 1 269 bp was cloned from Planomicrobium sp. 547 using primers designed based on the conserved sequences of proteases in GenBank. The Planomicrobium sp. 547 protease contained a domain belonging to the peptidase S8 family, which has a length of 309 amino acid (AA) residues. The alignment and phylogenetic analysis of the AA sequence indicated that the protease belonged to the subtilisin family.  相似文献   

19.
A bioflocculant producing potential bacteria was isolated from the circulating seawater of bio-filter using streak plate methods. The bacteria was identified through biochemical characteristics, partial 16 S ribosomal ribonucleic acids(rRNA), nucleotide sequencing, and BLAST analysis of the gene sequence that showed the bacteria have 99% similarity to Pseudoalteromonas sp.and deposited in GenBank as Pseudoalteromonas sp. NUM8 with accession number JX435820. Influences of time course assay,carbon sources, nitrogen sources, inoculum size, as well as initial pH on the bacteria producing extracellular bioflocculant activity were investigated. The results showed that the strain optimal production period of microbial bioflocculant was at 72 h(flocculating activity of 94.5%), then dropped slowly. The bacteria optimally produced the bioflocculant when 1.0% sucrose and 0.5% sodium nitrate were used as sole sources of carbon and nitrogen with flocculating activities of 92.8% and 93.8% respectively. Also, the bacteria produced the bioflocculant optimally when initial pH of the medium was 5.0(flocculating activity 93.2%), and when Ca~(2+)was used as cation(flocculating activity 93.4%). The culture condition of inoculum size of 3%(v/v) was optimal flocculant production(flocculating activity 94.4%). Composition analyses indicated the bioflocculant to be principally a glycoprotein made up of about 34.3% protein and 63.4% total carbohydrate.  相似文献   

20.
The present study was conducted to determine the change of digestive physiology in sea cucumber Apostichopus japonicus(Selenka) induced by corn kernels meal and soybean meal in diets. Four experimental diets were tested, in which Sargassum thunbergii was proportionally replaced by the mixture of corn kernels meal and soybean meal. The growth performance, body composition and intestinal digestive enzyme activities in A. japonicus fed these 4 diets were examined. Results showed that the sea cucumber exhibited the maximum growth rate when 20% of S. thunbergii in the diet was replaced by corn kernels meal and soybean meal, while 40% of S. thunbergii in the diet can be replaced by the mixture of corn kernels meal and soybean meal without adversely affecting growth performance of A. japonicus. The activities of intestinal trypsin and amylase in A. japonicus can be significantly altered by corn kernels meal and soybean meal in diets. Trypsin activity in the intestine of A. japonicus significantly increased in the treatment groups compared to the control, suggesting that the supplement of corn kernels meal and soybean meal in the diets might increase the intestinal trypsin activity of A. japonicus. However, amylase activity in the intestine of A. japonicus remarkably decreased with the increasing replacement level of S. thunbergii by the mixture of corn kernels meal and soybean meal, suggesting that supplement of corn kernels meal and soybean meal in the diets might decrease the intestinal amylase activity of A. japonicus.  相似文献   

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