Evaluation of lipid-producing yeast for biodiesel production

FUNGAL xylanase and lignin peroxidase enzymes were used as pretreatment for biobleaching of bagasse biopulping treated with mixed culture of Ophiostoma piliferum and Ceriporiopsis subvermispora SS- 33 at 27°C for one week in MV medium as static culture before the pulping with propylene glycol [PG]. Some agricultural wastes such as corn cobs, wheat bran and bagasse powder were used as a sole carbon source for xylanase production. The maximum production of fungal xylanase was attained after 7 days- fermentation period on corn cobs medium at 30°C on rotary shake flasks at 150 rpm. The enzyme production by Trichoderma reesie NRRL 6156 increased 1.17 fold as compared with that obtained by Trichoderma viride NRRL 13034.Using 10.30 IU xylanase/g bagasse biopulp, produced by Trtchoderma reesie NRRL 6156, for 4 h at 50°C was the best xylanase pretreatment which reduced klason lignin% and increased the brightness % of bagasse biopulp. The solid-state HC-LN medium supplemented with tween 60 and veratryl alcohol in addition to 10 grams of bagasse pulp was the best one for lignin peroxidase production by Phanerochaete chrvsosporium NRRL 6361, the enzyme activity of this treatment [77.75 IU/L] was higher than that obtained using semi-solid [47.75 IU/L] and liquid [36.50 IU/L] state, after 6 days incubation period. The optimum lignin peroxidase dose, for the best biobleaching of unbleached bagasse biopulp at 37°C for 8 h was 1.54 lU/g. Using these enzyme pretreatments led to increase the brightness %, breaking length and tear factor 6.7, 18.89 and 12.7 % by xylanase bleached bagasse [XBB] and 8.94 %, 34.92 and 30.82 %, by lignin peroxidase bleached bagasse [LBB], respectively. The enzyme treatment of LBB and XBB led to decrease of chlorine consumption 40% and 26.67 % as compared to control. Scanning electron microscope [SEM] of bleached bagasse pulp clearly showed fiber that exposed to enzymes treatment had a more open surface and it becomes more accessible to subsequent bleaching agents. The biologicaly pretreatment of bagasse pulp with xylanase orlignin peroxidase enzymes led to increase in the crystallinty by 11.29 and 8.3 %, respectively

Ecological studies on soil indigenous rhizobia in Egypt 3-Intrinsic antibiotic Resistance [TAR] for differentiation of rhizobia

antibiotic marking is generally used in following up the persistence of induced rhizobial strains to soils. As well known maximizing symbiotic N[2] fixation requires a great understanding of the ecology of rhizobia. One of the major limitations in study of this symbiosis is the difficulty in recognizing strains of rhizobia in their natural habitats. Intrinsic antibiotic resistance [IAR] of 131 Rhizobium isolates 381 belonging to clover, 21 to chickpea and 29 to pea towards low, moderate and high concentrations of 13 antibiotics was investigated. All isolates possessed IAR character but the number of antibiotics resisted varied and the resistance ability of most isolates decreased with the increase of antibiotic concentration in the culture medium [YMA]. Use of low or moderate concentrations gave more reliable information about the IAR character. Gentamycin and Kanamycin have the most suppressive effect on the three species of tested rhizobia, R. leguminosarum bv. trifolii, R. spp. and R. leguminosarum bv. viceae. Chickpea Rhizobium was also affected by streptomycin at the three levels of concentration, while pea isolates severely affected also by polymyvin especially at moderate and high levels of antibiotic since none isolates could grew on the medium Spectinomycin was of moderate effect on growing of pta Rhizobium

Antimicrobial activity of some Egyptian medicinal and aromatic plant waste extracts

A comparative study on the antimicrobial activity of some medicinal and aromatic plant wastes was done on a number of bacterial and fungal strains adopting the discdiffusion assay. Thirty extracts from Allium sativum L., Cympopogon sp., Nigella satival l., Ocimum basilicum L. and Thymus basilium were evaluated. Thymus basilium possessed the highest antimicrobial effect followed by Nigella sativa L., with respective average inhibition zone diameters of 4.7 and 3.8 mm. Fungal candidates were inhibited by plant extracts to higher extents as compared to bacterial strains, [inhibition zones measured were 5.9 mm for the former and 3 mm for the latter]. No remarkable variations were observed among the two methods used for extraction. The photochemical screening of plant waste extracts indicated the presence of carbohydrates, tannins, alkaloids, flavonoids, sterols, saponins and coumarins

Nitrogen fixation efficiency of rhizobia nodulating Apios americana.

In this study, the efficiency of Apios rhizobial isolates in N2 fixation was compared with a typical Bradyrhizobium strain [USDA 3451] in a greenhouse pot experiment. The study exhibited marked differences among Apios isolates in a nodule number and nodule mass top dry weight and total uptake of nitrogen by-plant. There were approximately two-fold differences in nitrogen accumulated within the plant between the most and the least effective isolate. The study also revealed that all isolates of Apios rhizobia [B. Sp.] gave a significant growth response despite the presence of indigenous B. Sp. [Vigna]. The differentiation between Apios isolates in their efficiency to fix atmospheric N was assessed using acetylene reduction technique for measuring N-ase activity. Data also showed that there were significant differences in the amount of N fixed between the different isolates of Apios

Bio-indicators of soil fertility in sugar cane rotation

The relationship between soil biological activity and soil fertility was studied under sugar cane rotation to find out whether or not the biological activity of the soil can be used as an index to soil fertilityThe results showed differences in soil enzyme activities [dehydrogenase, invertase, phosphatase and urease] at the different locations according to soil fertility levelA significant positive correlation between the enzyme activities and organic matter content was foundOn the other hand, a significant positive correlation was found between the enzyme activities and the microbial populations as well as CO2 evolution playing an important role in the release of essential nutrients for plantTherefore, enzyme activities can be used as an index to soil fertility level

Bio-indicators of soil fertility in rice rotation

The relationship between enzyme activities and some soil properties under rice rotation at two governorates was studied to find out whether or not the enzyme activities can be taken as a bioindicator to soil fertility. The results indicated that there are clear differences in soil enzyme activities [dehydrogenase, phosphatase, invertase and urease] at the different localities of the two governorates according to its soil fertility level. Significant positive correlation was established between the activities of dehydrogenase and urease and total bacterial counts, total fungi, phosphate-dissolving bacteria [PDB], ureolytic microorganisms and CO2 evolution. Phosphatase activity was positively correlated with total baccarat counts, total fungi and CO2 evolution but not correlated with PDB and ureolytic organisms. On the other hand, positive correlations were detected between invertase activity and each of total fungi, PDB, ureolytic organisms and evolved CO2

Bio-indicators of soil fertility in cotton rotation

The correlation assessment of the bioindicators and classical chemical indicators of soil fertility can help in testing the practical application of the bioindicators as alternative approach for soil fertility evaluations. The relationship between enzyme activities and some soil properties under the cotton rotation at three governorates was studied to find out whether or not the enzyme activities can be taken as bioindicator to soil fertility. The results showed that there were differences in soil enzyme activities [dehydrogenase, invertase, phosphatase and urease] at the different sites within the three governorates according to its soil fertility level. Also, a significant positive correlation was found between the enzyme activities and soil organic matter content and clay fraction%. Significant positive correlations were also established between the activity of each of the studied enzyme and the microbial population, which are the functions of the essential nutrients of the soil

Response of berseem clover Trifolium alexandrinm to rockphosphate fertilization and dual inoculation with rhizobium and vesicular arbuscular mycorrhiza VAM

sh: :w!: not found fertilization, Rhizobium and mycorrhizae inoculation were practiced. Highest green fodder yield, nodulation along with N and P content of plant were obtained at the second and third cuts whereas, lowest values were recorded with both 1st and 4th ones. The dual inoculation of clover with rhizobia and mycorrhizae improved plant growth parameters compared to the single inoculation practice. Rockphosphate always induced increase in plant growth parameters either with single or double inoculation practice. Root colonization with VAM increased due to inoculation practice with both rhizobia and mycorrhizae. This increase was more pronounced with the interaction between the two symbionts particularly at the second and the third cuts in the presence of rockphosphate

Performance of soybean as affected by bradyrhizobium japonicum and VA mycorrhiza under different levels of and N fertilization

The response of soybean to dual inocatlation with B. joponicwn and VAM fungi was evaluated at different levels of N and P fertilization. A greenhouse pot experiment was conducted, VAM and B. japonicum inoculant were applied either alone or combined with different levels of P and N fertilization. Phosphorus fertilization improved nodulation on plant roots, however it was inhibitory for both VAM spore density in soil and VAM colonization percentage of roots. Both rhizobia and VAM improved significantly the plant growth. This effect was extended until the seed filling and maturity stage of plant. The interaction between the host and two symbionts was more efficient on plant growth and its content of N and P

Effectiveness of fast-and slow-growing soybean rhizobia on some commercial soybean cultivars

Twelve genotypes of soybean were examined for effectiveness of N2 fixing symbiosis with fast-and slow-growing soybean rhizobia in a greenhouse pot experiment. Plant introductions were inoculated with five fast-growing strains of rhizobium fredii [USDA HH003 HH103, HH303, 191 and 205] or six slow-growing strains of Bradyrhizobium japonicum [USDA 24, 31, 123 and mixed inoculum of USDA 6, 110 and 136]. Seven-week old plants were assessed for nodule dry weight, plant-top dry weight, and nitrogen accumulation. Statistical analyses showed that the combined genotype-stains effect was responsible for all the variation observed in all parameters. In general, the slow- growing strains formed effective nodules on all soybean genotypes, except strain USDA 24. The fast-growing rhizobia strains were less effective on most of soybean genotypes particularly strains USDA 191 and 205. There were significant differences in plant-top dry weight among the different soybean genotypes due to the interaction with the different strains of soybean rhizobia. The interaction between soybeen genotypes and the different strains revealed less top dry weight accumulation with strains USDA 191, 205 and 24. Among soybean genotypes, large differences were observed in N2 fixed due to the inoculation with the different R. japonicum strains. In same way, the same cultivar responded differently to the different strains. The high response of N2 fixation was obtained from the interaction between the cultivar Jupiter and the slow-growing Mix rhizobia strains [6, 110, and 136]

Rhizobial population and effectiveness of peat base inoculants produced by diluted and undiluted culture using septic and aseptic methods

Experiments were conducted to determine which method of inoculant preparation, either undiluted or 1,000-fold diluted culture under septic and aseptic condition, is the proper one to compare the evaluation techniques. Enumeration of rhizobia was determined by plate count and plant infection most probable number [MPN] techniques. All the inoculants were uniformly high in quality [greater than 10 rhizobia/ g moist peat] and there were no marked differences in rhizobia population despite the great difference in initial inoculum levels. Counts with the two methods were acceptable, but values obtained by the MPN were generally slightly lower. However, the MPN technique was the only effective method in estimating the viable count of rhizobia with the tray method of inoculant production. The effectiveness of inoculants produced with diluted culture and autoclaved peat did not differ significantly from that of inoculants produced with undiluted culture. The tray method-diluted culture technique enables production of larger quantities of legume inoculants at lower cost

Studies on rhizobium strains TAL 582, 1145 and 600 of leucaena and prosopis spp

Experiments were carried out in a greenhouse and in the laboratory to study the nodulation pattern, effectiveness, nitrogen fixation efficiency and competition between three Rhizobium strains TAL 582, 1145, and 600, using their cross inoculation hosts Leucaena and Prosopis sp. Two types of single-strain inoculate were prepared with neutralized fine and granular peat. The three strains were identified by immunofluorescence technique using the direct and indirect method. Generally, the nodule number, dry weight and nitrogen uptake by plants as a result of soil inoculation with the mixed single strain of fine peat were better than the granular one, comparison amongst the strains showed marked differences in their ability to form nodules on the plant roots, consequently the dry weights and N-uptake ty the hosts were affected. The host L. leucocephala-K3 was better than P. pallida. L. Diversifolia formed no nodules with with TAL 582 and small nodules with the other two strains. In terms of efficiency and infectivity Rhizobium strains could be ranked as TAL 1145 greater than 600 greater than 582. The most susceptible host was L. Leucocephala. Examination of the stains by the immunodiffusion technique indicated that all the strains were highly specific

Evaluation of the composting sheath of peanut pods as a local carrier for Rhizobium inoculants production

The quality of the compositing sheath of peanut pods as a rhizobial carrier compared to granular peat was determined by the plate count methods and the plant infection test [MPN] using Rhizobium japonica strain CB 1809. The effectiveness of rhizobial inoculation of soybean cv. Williams was carried out by Leonard jar technique in a controlled growth chamber. The plate count method, gave significantly higher numbers of rhizobia than the MPN. In general, the granular inoculum contained more rhizobia than the peanut sheath inoculum. The addition of some nutrients at the beginning of the compositing process apparently failed to enhance multiplication of the tested rhizobial strain within the peanut sheath carrier. Data of the N2 fixation efficiency of the nodular plants showed that although the granular peat is still the overall best carrier for rhizobia, the compositing sheath of peanut pods is satisfactory in supporting rhizobial multiplication and survival

Field assessment of plant density effect on biological nitrogen fixation by faba beans [vicia faba]

Field experiments were conducted to study the effects of increasing plant density on symbiotic nitrogen fixation by the faba bean /Rhizobium leguminosarum system. Increasing plant density increased the dry matter content of plants. The well nodulated plants had a greater N-uptake, than those plants fertilized with nitrogen. Plant densities up to 160,000 plants/feddan increased pod and seed yields. The results also showed that biological N2-fixation by faba beans was sufficient to supply all the N needed for the plants. However, the limiting factor for yield response, with increasing plant density, is likely to be due to a reduced photosynthetic capacity of the plant population within the limited area