Inoculum Rate Research Articles

Optimisation and Modelling of Anaerobic Digestion of Whiskey Distillery/Brewery Wastes after Combined Chemical and Mechanical Pre-Treatment

Whiskey distillery waste streams consisting of pot ale (liquid residue) and spent grain (solid residue) are high strength organic wastes and suitable feedstock for anaerobic digestion (AD) from both economic and environmental stand points. Anaerobic digestion of pot ale and pot ale/spent grain mixtures (with mixing ratios of 1:1, 1:3, and 1:5 by wet weight) was performed after implementation of a novel hybrid pre-treatment (combined chemical and mechanical) in order to modify lignocellulosic structure and ultimately enhance digestion yield. Lignin, hemicellulose, and cellulose fractions were determined before and after chemical pre-treatment. Effects of different inoculum rates (10–30–50% on wet basis) and beating times (0–7.5–15 min) on anaerobic digestion of pot ale alone and of pot ale/spent grain mixtures were investigated in lab scale batch mode with a major focus of optimising biogas yield by using response surface methodology (RSM) in Design Expert Software. The highest biogas yields of 629 ± 8.5 mL/g vs. (51.3% CH4) and 360 ± 10 mL/g vs. (55.0 ± 0.4) with anaerobic digestion of pot ale alone and spent grain mix after 1M NaOH and 7.5 min beating pre-treatments with 50% inoculum ratio respectively. The optimum digestion conditions to maximise the biogas quality and quantity were predicted as 10 and 13 min beating times and 32 and 38 °C digestion temperatures for anaerobic digestion of pot ale alone and spent grain mix respectively.

Enhancing treatability of tannery wastewater by integrated process of electrocoagulation and fungal via using RSM in an economic perspective

Abstract The wastewater from tannery industry, using single treatment technology has not been enough to remove the chromium (Cr6+) or high organic content (COD). Electrocoagulation (EC) and Biological Fungal Treatment (BFT) which endure against toxic and/or highly organic content, are promising technologies to eliminate impurities of tannery wastewaters. In this study, the treatment performance of integrated EC and BFT processes via response surface methodology (RSM) was investigated for the tannery wastewater to determine the effects of operating variables. The factors of electrode combination (Al–Fe), pH (4–8), current density (0.54–0.81 A), and electrolysis time (15–60 min) are investigated for EC and inoculum rate (0.5–2%) reaction time (6–36 h) and pH (4–6) are also investigated for BFT. The operating cost of the combined process was calculated as 1.73 $.m−3. It was determined that efficient COD (63.8%) and Cr6+ (90%) removal were achieved via EC (pH 8.0, 60 min reaction time and 0.81 A current). The optimum condition of BFT for COD and Cr6+ removal are at pH 5.0, 36 h reaction time and 2% inoculum rate. Total efficient COD (96%) and Cr6+ (97%) removal were achieved at EC and BFT with the combined system.

Enhanced endoxylanase production by Myceliophthora thermophila with applicability in saccharification of agricultural substrates.

The production of enzymes by solid-state fermentation is an interesting process and currently used worldwide as it can be carried out in solid matrix in absence of free water. In present study, Myceliophthora thermophila BJTLRMDU3 produced high titres of endoxylanase (890.55U/g DR, dry residue) using 5g rice straw at pH 7.0 and at 45°C with 1:7 (w/v) solid-to-moisture ratio with inoculum rate of 12 × 106 spores/ml after 4days in solid-state fermentation. High enzyme titre was produced after moistening the rice straw with solution containing ammonium sulphate (0.4%), K2HPO4 (1.0%), MgSO4·7H2O (0.3%), FeSO4·7H2O (0.03%) and CaCl2 (0.03%). Addition of sucrose (2% w/v) and ammonium nitrate (2% w/v) further enhanced the endoxylanase production. A high endoxylanase production was achieved at water activity (a W) of 0.95 (1639.80U/g DR) that declined drastically below this value. Among different surfactants, Tween 20 (3% v/v) enhanced the secretion of endoxylanase (2047.91U/g DR). Furthermore, on optimization of K2HPO4 concentration, it was found that 0.5% K2HPO4 improved (2191.28U/g DR) endoxylanase production and overall 4.35-folds increase in production of endoxylanase was achieved after optimization of culture conditions. The enzyme has potential to liberate monomeric (xylose) as well as oligomeric (xylotiose, xylotetrose, and xylopantose) sugars from xylan. On saccharification of rice straw and corncob with endoxylanase, maximum yield of reducing sugars was 135.61 and 132.61mg/g of substrate recorded after 48, and 36h, respectively.

Using Yield Response Curves to Measure Variation in the Tolerance and Resistance of Wheat Cultivars to Fusarium Crown Rot.

The disease crown rot, caused predominantly by the fungal pathogen Fusarium pseudograminearum, is a major disease of winter cereals in many regions of the world, including Australia. A methodology is proposed, using response curves, to robustly estimate the relationship between grain yield and increasing crown rot pathogen burdens. Using data from a field experiment conducted in northern New South Wales, Australia in 2016, response curves were derived for five commercial wheat cultivars exposed to six increasing rates of crown rot inoculum, where the rates served to establish a range of crown rot pathogen burdens. In this way, the response curve methodology is fundamentally different from alternate approaches that rely on genetic or environmental variation to establish a range in pathogen burdens over which yield loss relationships are estimated. By manipulating only the rates of crown rot inoculum and, thus, pathogen burden directly, the number of additional confounding factors and interactions are minimized, enabling the robust estimation of the rate of change in yield due to increasing crown rot pathogen burdens for each cultivar. The methodology revealed variation in the rate of change in yield between cultivars, along with the extent of crown rot symptoms expressed by the cultivars. Variation in the rate of change in yield between cultivars provides definitive evidence of differences in the tolerance of commercial Australian wheat cultivars to crown rot caused by F. pseudograminearum, while variation in the extent of crown rot symptoms signifies differences in the resistance of the cultivars to this disease. The response curve methodology also revealed variation in how the different mechanisms of tolerance and resistance act to limit yield losses due to crown rot for different cultivars.

A novel microbial consortium from sheep compost for decolorization and degradation of Congo red

Congo red is a synthetic azo-dye dye with many industrial applications. The effluents containing azo dyes are causing several environmental hazards and thus should be treated prior to their discharge. The present work investigates the possible use of a novel microbial consortium from sheep compost for the decolorization of Congo red dye. The effect of different parameters including contact time, dye concentration and inoculum concentration on dye decolorization were investigated. The kinetic of dye decolorization was also assessed and the biodegradation of the dye was confirmed by different techniques. The results showed that the microbial consortium decolorized about 98% of Congo red (500 mg/L) after 24h. The efficiency of the decolorization decreased from 95% to 62% when the dye concentration increased from 100 to 500mg/L. Also, it was noticed that 75% of Congo red (25 mg/L) was decolorized at an inoculum rate of 2.5%. The kinetic results suggested that the decolorization of Congo red by the studied consortium follows the first order kinetic model. Also the maximum substrate consumption rate (Vmax) according to Michaelis- Menten model was found to be 19.30 mg/h/L and the decolorization rate constant (Km) was 116.93 mg/L. The biodegradation of Congo red was further confirmed by HPLC and GC-Ms analysis which revealed the presence of some spectral differences between the untreated dye sample and the treated one. In conclusion, the results of the present work suggest that microbial consortium from sheep compost could have potential application for bioremediation of industrial effluents containing Congo red dye.

Rice Bran or Apple Pomace? Comparative Data Analysis of Astaxanthin Bioproduction

Modeling and optimization of high value-added astaxanthin pigment bioproduction statistically by Sporidiobolus salmonicolor ATCC 24259 from two substantial wastes, rice bran (RB) and apple pomace (AP) was aimed in this study. The experimental data was obtained at constant inoculum rate (2%) and particle size (0.85 mm) for both wastes by conducting 17 runs, which were generated by Box-Behnken design. 33.41 µg astaxanthin gRB- and 77.31 µg astaxanthin gAP- were produced as the maximum amount at the end of fermentation period, 10 days. Apple pomace was concluded as the optimized waste for the production of astaxanthin based upon the highest yield. Predicted response results of response surface methodology (RSM) and radial basis function-neural network (RBF-NN) were compared in order to evaluate the accuracy of two methodologies on non-linear behavior of the astaxanthin bioproduction. RBF-NN became prominent with its well-suited to apple pomace fermentation system by resulting in quite low 0.8495, root mean square error (RMSE), 0.3349, mean absolute error (MAE), and 0.9985, correlation coefficient (CC) as best measures of a model performance.

Inhibition of volatile fatty acids on methane production kinetics during dry co-digestion of food waste and pig manure

Compared with wet digestion, dry digestion of organic wastes reduces reactor volume and requires less energy for heating, but it is easily inhibited by high volatile fatty acid (VFA) or ammonia concentration. The inhibition on methane production kinetics during dry co-digestion of food waste and pig manure is rarely reported. The aim of this study was to explore the inhibition mechanisms and the microbial interactions in food waste and pig manure dry co-digestion systems at different inoculum rates (25% and 50% based on volatile solids) and food waste/pig manure ratios (0:100, 25:75, 50:50, 75:25 and 100:0 based on volatile solids). The results showed that the preferable operation conditions were obtained at the inoculum rate of 50% and food waste/pig manure ratio of 50:50, with a specific methane yield of 263 mL/g VSadded. High VFA concentration was the main inhibition factor on methane production, and the threshold VFA inhibition concentrations ranged 16.5–18.0 g/L. Syntrophic oxidation with hydrogenotrophic methanogenesis might be the main methane production pathway in dry co-digestion systems due to the dominance of hydrogenotrophic methanogens in the archaeal community. In conclusion, dry co-digestion of food waste and pig manure is feasible for methane production without pH adjustment and can be operated stably by choosing proper operation conditions.

Complementary effect of thermotolerant yeast and cold active cellulase on simultaneous saccharification and fermentation for bioethanol production from rice straw

The present investigation aimed towards the optimization of bioethanol production from alkali pretreated rice straw using thermotolerant Saccharomyces cerevisiae JRC6 strain which was capable of fermenting glucose at 40 °C with a fermentation efficiency of 91.14%. Four process variables, namely, substrate loading (4.0%–7.0% w/v), enzyme loading (10–30 FPU/g dry rice straw), pH (4.0–6.0), and inoculum rate (7.0%–15.0% v/v), were evaluated by response surface methodology using Box Behnken Design to develop a simultaneous saccharification and fermentation process for bioethanol production using thermotolerant yeast and cold active cellulase cocktail produced by Aspergillus niger SH3. Among these variables, pH was the most significant factor followed by substrate loading. The optimum outcomes of the design were as follows: substrate loading (6.71% w/v), enzyme loading (25.71 FPU/g dry rice straw), pH (4.15), and inoculum rate (13.2% v/v). The validation experiment with the optimized parameters resulted in a better ethanol concentration of 12.95±0.39 g/L within 24 h at 40 °C. The results obtained indicated that the process may further be scaled up as a single pot process with substantial energy saving because the saccharification temperature was 10 °C lower as compared to commercial cellulases, and one step has been reduced due to the combined action of the enzyme and yeast.

Within-Host Competition between Two Entomopathogenic Fungi and a Granulovirus in Diatraea saccharalis (Lepidoptera: Crambidae).

We provide insights into how the interactions of two entomopathogenic fungi and a virus play a role in virulence, disease development, and pathogen reproduction for an economically important insect crop pest, the sugarcane borer Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae). In our model system, we highlight the antagonistic effects of the co-inoculation of Beauveria bassiana and granulovirus (DisaGV) on virulence, compared to their single counterparts. By contrast, combinations of Metarhizium anisopliae and B. bassiana, or M. anisopliae and DisaGV, have resulted in additive effects against the insect. Intriguingly, most cadavers that were derived from dual or triple infections, produced signs/symptoms of only one species after the death of the infected host. In the combination of fungi and DisaGV, there was a trend where a higher proportion of viral infection bearing conspicuous symptoms occurred, except when the larvae were inoculated with M. anisopliae and DisaGV at the two highest inoculum rates. Co-infections with B. bassiana and M. anisopliae did not affect pathogen reproduction, since the sporulation from co-inoculated larvae did not differ from their single counterparts.

Effect of temperature and inoculum density on disease intensity of Phytophthora parsiana

ABSTRACT- The effects of inoculum density and temperature on the disease intensity of Phytophthora parsiana on almond seedlings were investigated. Almond seeds (Rabie and Kaghazi cultivars) were placed in moist vermiculite at 4°C for 45 days. Germinated seeds were sown in a soil: sand mixture (2:1 v/v) and grown in greenhouse (18°C-25°C). One-month-old seedlings were transferred from the greenhouse to the growth chambers set at 15, 18, 20, 25,30 and 32°C. The seedlings were subsequently inoculated either with mycelium of P. parsiana grown for 4-6 weeks on vermiculite amended with hemp seed extract or with zoospore (103, 104, 105 and 106 ml-1) by root dip method. The effect of temperature, inoculum density and their interaction on seedling mortality was measured. The results indicated that all three factors had significant effects on seedling mortality. While the highest disease incidence (100% mortality in almond seedlings) occurred at 30°C and 32°C, no mortality was observed at 15°C and18°C. Increasing temperature from 20°C to 30°C and inoculum rate from 103 to 106 zoospores ml-1 increased disease incidence significantly. Higher temperatures and inoculum densities also caused significant increases in the colonization level of the crown, main and lateral roots as well as reductions in the fresh and dry root weights of the seedlings.

Rice Bran or Apple Pomace? Comparative Data Analysis of Astaxanthin Bioproduction

Modeling and optimization of high value-added astaxanthin pigment bioproduction statistically by Sporidiobolus salmonicolor ATCC 24259 from two substantial wastes, rice bran (RB) and apple pomace (AP) was aimed in this study. The experimental data was obtained at constant inoculum rate (2%) and particle size (0.85 mm) for both wastes by conducting 17 runs, which were generated by Box-Behnken design. 33.41 μg astaxanthin n gRB- and 77.31 μg astaxanthin gAP- were produced as the maximum amount at the end of fermentation period, 10 days. Apple pomace was concluded as the optimized waste for the production of astaxanthin based upon the highest yield. Predicted response results of response surface methodology (RSM) and radial basis function-neural network (RBF-NN) were compared in order to evaluate the accuracy of two methodologies on non-linear behavior of the astaxanthin bioproduction. RBF-NN became prominent with its well-suited to apple pomace fermentation system by resulting in quite low 0.8495, root mean square error (RMSE), 0.3349, mean absolute error (MAE), and 0.9985, correlation coefficient (CC) as best measures of a modelperformance.

Inoculum Rate Effects on the Soybean Symbiosis in New or Old Fields under Tropical Conditions

Core Ideas Inoculum rate with elite strains is critical to achieve the benefits of biological N2 fixation. The minimum rate of 1.2 × 106 cells of Bradyrhizobium seed−1 was determined to benefit biological N2 fixation. Soybean can highly benefit from biological N2 fixation. Some sites required 2.4 × 106 cells seed−1 and could respond to higher rates. Soybean [Glycine max (L.) Merr.] can highly benefit from inoculation with elite strains of Bradyrhizobium, selected for high capacity of N2 fixation. However, to achieve the benefits, the strains must be capable of effectively nodulate the host, and inoculum rate may be critical, especially under stressing tropical environmental conditions. We performed 10 field experiments, in four crop seasons and four Brazilian states, including soils without and with established populations of soybean bradyrhizobia, to investigate the effects of inoculum rates, consisting of zero, 0.6 × 106, 1.2 × 106, and 2.4 × 106 colony forming units (CFU) per seed. Nodule number and dry weight were evaluated at early flowering and grain yield and N content in grains at the physiological maturity. Satisfactory nodulation and grain yields were obtained with 1.2 × 106 CFU seed−1. However, there were sites with and without established population of bradyrhizobia where maximum nodulation and/or yields were achieved with inoculum rate of 2.4 × 106 CFU seed−1, and that could require even higher rates. Therefore, we suggest the adoption of the minimum inoculum rate of 1.2 × 106 cells of Bradyrhizobium seed−1 for soybean planting in the tropics, to achieve maximum contribution of biological N2 fixation.

Outdoor Growth Characterization of an Unknown Microalga Screened from Contaminated Chlorella Culture.

Outdoor microalgae cultivation process is threatened by many issues, such as pest pollution and complex, changeable weather. Therefore, it is difficult to have identical growth rate for the microalgae cells and to keep their continuous growth. Outdoor cultivation requires the algae strains not only to have a strong ability to accumulate oil, but also to adapt to the complicated external environment. Using 18S rRNA technology, one wild strain Scenedesmus sp. FS was isolated and identified from the culture of Chlorella zofingiensis. Upon contamination by Scenedesmus sp., the species could quickly replace Chlorella zofingiensis G1 and occupy ecological niche in the outdoor column photobioreactors. The results indicated that Scenedesmus sp. FS showed high alkali resistance. It also showed that even under the condition of a low inoculum rate (OD680, 0.08), Scenedesmus sp. FS could still grow in the outdoor raceway pond under a high alkaline environment. Even under unoptimized conditions, the oil content of Scenedesmus sp. FS could reach more than 22% and C16–C18 content could reach up to 79.68%, showing that this species has the potential for the biodiesel production in the near future.

Bioprocess for phytase production by Ganoderma sp. MR-56 in different types of bioreactors through submerged cultivation

The aims of this study were to optimize the medium composition, culture conditions and define a bioprocess using types of bioreactor to increase phytase production through submerged cultivation by Ganoderma sp. MR-56. Metal salts, carbon and nitrogen sources had been evaluated upon the overall enzyme production on wheat bran broth. The results showed increase of 81, 95 and 36% of phytase activity, compared to control, by the supplementation of soybean molasses, yeast extract and CaCl2, respectively. Phytase activity in optimized medium reached 14.5UmL⿿1, a 5.8-fold increase compared to control. Also, at optimized medium, the associated effects of culture conditions as vessel type and aeration were achieved at 30°C, pH 6.0 and 3% inoculum rate. Maximum phytase production was obtained in Dreschel bottles at 2.0 vvm, which resulted in 20.9UmL⿿1 at 264h and productivity of 0.08UmL⿿1h⿿1, while 11.1UmL⿿1 in Erlenmeyer Flasks at 96h (productivity of 0.12UmL⿿1h⿿1). The greatest productivity was 0.14UmL⿿1h⿿1obtained in stirred tank reactor and reaching 10.3UmL⿿1 of phytase activity at 72h. Overall, was proven that Ganoderma sp. MR-56 can successfully produce phytase in different bioreactors through submerged cultivation using a by-product medium.

Effect of Arbuscular Mycorrhizal Inoculum Rate on Tomato (Lycopersicum esculenta L.) Seedlings

An experiment on the effect of rate of arbuscular mycorrhiza inoculum in producing tomato seedlings (var. Ratan) were conducted in the seedbed of Soil Science Division, Bangladesh Agricultural Research Institute, Joydebpur, Gazipur, Bangladesh during rabi season of 2007-08 and 2008-09. Seven rates of AM inoculum viz. 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 kg m-2 were studied on tomato seedlings. Cowdung was used at the rate of 5 kg m-2 as basal. Seeds were sown in 10 cm apart solid lines on 13 November 2007 and 11 November 2008, and the seedlings were thinned down to about 3 cm from seedling to seedling within a week of germination. Ratan was used as the variety of tomato. Biomass yield, seedling height and nutrient uptake by tomato seedlings increased greatly with the use of AM inoculum. Biomass yield of tomato seedlings followed quadratic trend with the increase of AM inoculum rate from 0 to 1.0 kg m-2 in 2007-08 and 0 to 2.0 kg m-2 in 2008-09.Bangladesh J Microbiol, Volume 29, Number 2, Dec 2012, pp 104-108

Efficacy of copper alternatives applied as stop-sprays against Plasmopara viticola in grapevine

The six products, Armicarb, Vitisan, lime sulphur, Caso, Calce Fiocco and Ulmasud were tested for their ability to control downy mildew (Plasmopara viticola) on grapevine (Vitis vinifera) in order to find effective alternatives to copper, a heavy metal that is commonly used as a fungicide in organic viticulture. Each product was applied to potted grapevines at i) 40°h (degree hours) and ii) 80°h after inoculation (ai) of the pathogen. These so-called stop-sprays were tested on plants that received two different P. viticola inoculum rates. The formulated potassium bicarbonate product Armicarb and lime sulphur reduced disease incidence and severity similar to or better than the copper hydroxide treatment. Armicarb and lime sulphur reduced disease incidence by up to 46 % and 22 %, respectively, and disease severity by up to 73 % and 77 %, respectively. However, observed effects were depending on both inoculum rates and time of application. Overall, the results indicate that the tested products showed higher efficacy when applied 40°h ai and when the pathogen was applied at the high inoculum rate, however, that was not always the case. The unformulated potassium bicarbonate product Vitisan and other products based on calcium chloride, calcium hydroxide and acid clay did not reliably affect disease incidence and severity. Possible roles of inoculum density, wetting agents, and sprinkler usage during the infection procedure are discussed.

Enhancement of fructosyltransferase and fructooligosaccharides production by A. oryzae DIA-MF in Solid-State Fermentation using aguamiel as culture medium

The aim of this work was to improve the production of fructosyltransferase (FTase) by Solid-State Fermentation (SSF) using aguamiel (agave sap) as culture medium and Aspergillus oryzae DIA-MF as producer strain. SSF was carried out evaluating the following parameters: inoculum rate, incubation temperature, initial pH and packing density to determine the most significant factors through Box-Hunter and Hunter design. The significant factors were then further optimized using a Box-Behnken design and response surface methodology. The maximum FTase activity (1347U/L) was obtained at 32°C, using packing density of 0.7g/cm3. Inoculum rate and initial pH had no significant influence on the response. FOS synthesis applying the enzyme produced by A. oryzae DIA-MF was also studied using aguamiel as substrate.

Evaluation of Paenibacillus spp. isolates for the biological control of black rot in Brassica oleracea var. capitata (cabbage)

ABSTRACTThe ability of isolates of Paenibacillus spp. to protect Brassica oleracea var. capitata (cabbage) against the black rot pathogen, Xanthomonas campestris pv. campestris (Xcc),was evaluated. Twenty-four isolates of Paenibacillus spp., isolated from New Zealand-grown brassica hosts or soil, were evaluated for in vitro antagonism towards six Xcc isolates. Seven Paenibacillus spp. isolates with different levels of in vitro suppressive activity against Xcc were screened in pot experiments for their capacity to reduce black rot symptoms on cabbage. Two Paenibacillus isolates (P10 and P16) exhibited biocontrol activity against Xcc, and four isolates (P1, P6, P9, and P24) reduced cabbage seed germination and seedling emergence. The dependence of bioactivity on inoculum rate was investigated with three Paenibacillus isolates (P6, P10, and P16) at three different concentrations (5 × 108, 5 × 109, and 5 × 1010 CFU ml−1). Negative effects on seedling emergence were detected with isolate P6 at concentrations ≥5 × 109 CFU ml−1. All three isolates applied at the three concentrations reduced black rot symptoms on the cotyledons and true leaves. There was poor or no relationship between the inhibitory effect of Paenibacillus spp. isolates on the growth of Xcc in vitro, and their biocontrol activity in vivo. Paenibacillus isolate P16 was identified as a potential biological control of black rot in cabbage.

Purification and characterization of a new neutral metalloprotease from marine Exiguobacterium sp. SWJS2.

Among the protease-producing bacterial strains isolated from deep-sea sediments, SWJS2 was finally selected and identified as genus Exiguobacterium. Plackett-Burman and orthogonal array designs were applied to optimize the fermentation conditions, and the results are as follows: Glucose 5g, yeast extract 15g, glycerin 2g and CaCl2 ⋅2H2 O 0.5g dissolved in 1 L artificial seawater; temperature 25°C, original pH 7, inoculum rate 2%, seed age 12 H, loading volume 25mL (250-mL Erlenmeyer flask), shaking speed 150 rpm, and fermentation time 44 H. The protease activity production was improved from about 80 to 660 U/mL under the optimized parameters. The protease was purified fourfold with specificity activity of 30,654.1 U/mg protein and a total yield of 16.2%. The protease exhibited the maximum activity at 40-45°C and pH 7. Moreover, the enzyme activity was found to be inhibited by Cu(2+) , Ba(2+) , Cd(2+) , Hg(2+) , and Al(3+) at 5 mM, whereas it can be increased by Mg(2+) , Mn(2+) , and Ca(2+) at 0.5-5 mM. The enzyme was totally inactivated by 1 or 5 mM ethylenediaminetetraacetic acid but not by phenylmethanesulfonyl fluoride, tyrpsin inhibitor from Glycine max (STI), benzamidine, 5,5'-dithio-bis-(2-nitro benzoic acid), or pepstatin A, suggesting that it belonged to metalloprotease.

Isolation, Identification and Optimization of Crude Oil Degrading Micromycetes for Biosynthesis of Poly Unsaturated Fatty Acids

Poly unsaturated fatty acids (PUFAs) participate in activities of all organisms from energy source to structural components. Disruption of metabolism results in diseases like atherosclerosis and obesity. In this work, optimal conditions to production of arachidonic, eicosapentaenoic and gamma- linolenic acids has been conducted in the oil degrading fungi-Cephalosporium humicola IE, Mucor globosus 11 and Pythium irregulare LX isolated from soils in Absheron peninsula, Azerbaijan. The fermentation process carried out at physicochemical conditions, carbon and nitrogen sources, temperature, pH, rate of inoculum, enzyme activity, exogenous fat and phosphate; as well as the stressful situations. Growth in crude oil as optimal carbon source showed that suitable nitrogen was peptone for lipid biosynthesis. In stable temperature the optimal lipid productionoccurred at 28°C, whereas in “temperature shifting technique”, greater yields occurred at 28°C for 5 days followed by at 15°C for 2 days. C/N ratio ranged from 4 to 64 and the optimal medium for production was composed of 2.0% glucose and 0.25% yeast extract, with addition of 0.1% KH2PO4 at neutral pH with 3% inoculum. Although the activities of the enzymes varied among the fungi, but the developmental profiles for all enzymes were practically similar. Additive fat and phosphate accelerated growth and enhanced PUFA production. Data showed that the procedure of adaptation of fungi motivated the increase of the rate of membrane phospholipids with a high quantity of PUFAs. This research is considered to be object of PUFA production as food supplements.