Fungal biotreatment of agro-industrial wastes for the production of bioethanol in bioreactor

BIOETHANOL production from lignocellulosic feedstocks is considered a promising strategy to increase global production of biofuels without impacting food supplies. This work aimed to evaluate bioethanol production by baker's yeast using a medium containing the hydrolysate of fungal biotreatment of five different lignocellulosic feedstocks with some amendments. The pretreatment of lignocellulosic feedstocks using 5 % w/v NaOH, 1 % v/v H[2]SO[4] and sodium hypochlorite: H[2]O[2][10:1] prior to fungal biotreatment was studied. For bioethanol production, batch, fed-batch [two strategies] and continuous cultivations of baker's yeast on the fungal biotreated rice straw hydrolysate was evaluated in bioreactor. In batch and pulsed fed-batch cultivations, the highest bioethanol concentration, conversion coefficient, bioethanol yield and productivity were [0.41 % v/v, 36.9 % v/w, 36,9 % v/w and 0.114 ml/l/h, respectively], while in fed-batch cultivation with continuous feeding these parameters were [0.45 % v/v, 40 % v/w,. 40.5 v/w % and 0,015 ml/l/h, respectively]. The highest bioethanol concentration [0.52 % v/v] was obtained in continuous culture at dilution rate of 0.03 h[-1]. while conversion coefficient; yield and productivity were 31.2 % v/w, 31.4 % v/w and 0.022 ml/l/h, respectively

Effect of gama irradiation of bioethanol producing microorganisms on bioethanol formation from sugarcane bagasse and potato peels

THE PRESENT work was designed to investigate the production of bioethanol from agriculture feedstock [sugarcane bagasse and potato peels] using Saccharomyces cerevisiae ATCC 7754 and Zymomonas mobilis ATCC 29191, exposed to different doses of gamma irradiation [0, 100, 300, 500, 1000 and 1500 Gy]. The effect of different hydrolysis pretreatments of feedstock on resulting sugars [initial sugars], which were later fermented to bioethanol, was also tested and compared to non-hydrolyzed feedstock. Hydrolysis of sugarcane bagasse and potato peels was conducted with dilute sulphuric acid [2 and 6 % v/v], running at 100 and 120°C for 30 and 60 min of retention time. The highest bioethanol concentration obtained from sugarcane bagasse was 10.3 gL[-1], which was produced by Sacch. cerevisiae ATCC 7754 irradiated at 300 Gy from hydrolysate of 2 % [v/v] H[2]SO[4] at 120°C for 60 min treatment. From the same treatment, the highest bioethanol concentration obtained by Z mobilis ATCC 29191 was 4.4 gL[-1], when irradiated at 100 Gy. This acid treatment produced 23.7 gL[-1] of sugars from the feedstock. The highest bioethanol concentration obtained from potato peels was 7.5 gL[-1], produced by Sacch. cerevisiae ATCC 7754 irradiated at 300 Gy from hydrolysate of 6 % [v/v] H[2]SO[4] at 100°C for 60 min treatment, followed by 5.7 gL[-1] produced by Z mobilis ATCC 29191 irradiated at 100 Gy. This treatment produced 24 gL[-1] of sugars from the feedstock

Optimization of biosurfactant production by bacillus licheniformis isolated from oil contaminated Egyptian soil

Optimal conditions for obtaining elevated biosurfactant production by a local strain of Bacillus licheniformis strain No. 5 were investigated. Modified minimal salt medium, pH 7.0, containing crude oil [1%], urea [2 g/l], KH[2]PO[4] + K[2]HPO[4] [2+2 g/l], MgSO[4] [0.2 g/l], yeast extract [1 g/l], and trace elements solution [0.1%] was found to be the most suitable for growth and emulsifying activity by this bacterium. High biosurfactant production was obtained after incubation for 7 days at 30° C. By providing the previous conditions, the emulsion index [E[24]%] was increased 3-fold as compared to that obtained via growth in the original minimal salt medium. In biorcactor batch culture, an agitation speed of 300 rpm attained the highest microbial growth [1.9 g cell dry weight/l] and an E[24]= 50.90% after 7 clays of incubation. In fed-batch culture, the pulsed addition of crude oil during the first 2 - 3 days of incubation enhanced the emulsification activity by 1.3-fold. The greatest E[24] was obtained using black grain oil [89.09%], followed by that obtained against diesel oil [87.27%]. The highest stability of emulsion index was recorded on diesel oil, which remained stable for 10 days [E[240]= 81.81%]. The biosurfactant showed an almost stable surface activity profile over a wide range of pH values [from 6 to 12]. The maximum emulsification activity was obtained at pH 8. The reduction in E[24] after exposure of the biosurfactant to 121°C for 15 min against diesel oil and toluene was 43.7% and 28.6%, respectively. Chemical analyses of the purified biosurfactant showed that it is a lipoprotein. Significant emulsification activity was detected towards different aliphatic and aromatic hydrocarbons and vegetable oils. The purified biosurfactant contained 41.7% C, 7.4% H and 5.8% N and was comprised of 36.2% proteins, 12.3% lipids and 5.6% carbohydrates

Production of polyhydroxyalkanoate [PHAs] and copolymer [P[HB-co-HV]] by soil bacterial isolates in batch and two-stage batch cultures

NINETY TWO local bacterial isolates, from the rhizosphere and soil around the root system of bean [Viciafaba] grown in Kalubia Governorate in Egypt, were bio-prospected for polyhydroxyalkanoate [PHA] accumulation. Three isolates accumulated >/=20% of PHAs, they were identified as Pseudomonas flu orescens S48, Bacillus megaterium 7A and B. megaterium UBFI9. The tested isolates gave the maximum PHAs content on basal medium containing glucose and ammonium sulfate at C/N ratio of 30/1 after 72 hr at 30°C using shake flask culture technique. Two-stage batch were implemented with varying loading levels of nitrogen and phosphorus, inoculated with washed cells. Nitrogen omission of 70% led to increase the PHAs content by 19%, 3% and 8.5% using washed cells of Ps. fluorescens S48, B. megaterium UBF 19 and Bacillus megaterium 7A, respectively comparing with batch production on the same medium after 72 hr. The Copolymer poly[hydroxybutyrate-co-hydroxyvalerate] [P [HB-co-HV]] content level was increased when valerie/glucose [V/G] was 0.19 mol.mo[-1] after 96 hr being 25.97% and 20.11% by Ps. fluorescens S48 and B. megaterium UBFI9, respectively and reached 23.73% by B. megaterium 7A at propionic/glucose [PIG] of 0.5 mol.mol[-1]. The corresponding highest values of valeric content of copolymer at V/G 3.08 mol.mol[-1] were 63%, 49% and 45%, respectively, comparing with other V/G ratios by using GC analysis . Replacing glucose with 2% corn oil or 1% soybean oil increased the PHAs content of Ps. fluorescens S48 cells to 54.21% and 52.12%, respectively, after 72

Appendicular mass revisited

Management and timing of surgery for appendicular mass is controversial. To audit the management of appendicular mass in Khartoum Teaching Hospital. Analysis of demographic and clinical data of 280 patients in the period Jan 2000 through Dec 2006. Out of 280 patients 104 [37.5%] were in the third decade. 204 [72.9%] had pain for more than five days and 136 [48.6%] had temperature >37.5°C. Conservative management was successful in 156 [55.7%] patients. 25 [8.9%] patients had emergency surgery. 28 [10%] patients came for follow up but refused surgery. Mucocele of the appendix and carcinoma of the caecum were found each in one patient. Emergency surgery was difficult in eight patients with failure to remove the appendix in one of them and faecal fistula developed in two. The conservative method is safe. However, cancer caecum may be missed. In contrast emergency surgery led to faecal fistula in two patients