Evaluation of Growth Yield of Spirulina maxima in Photobioreactors

The paper deals with the evaluation of the parameters for the cultivation of Spirulina maxima in two reactors (large-laboratory scale (LL) and semi-technical scale (ST)), whose illuminated areas in respect of the illuminated volume are different, and with the operating costs. We evaluated the growth yield coefficients for Spirulina maxima cultures. In the LL, the following factors were identified: YO2/X – 65.5; YX/CO2 – 0.0806; YX/P2O5 – 0.0082, while in the ST: YO2/X – 583; YX/CO2 – 0.017; YX/P2O5 – 0.0023. Although the reactor in the ST was equipped with many devices that should have improved the efficiency of cultivation, the obtained result was lower compared to the culture conducted in the LL. It was proved that it was possible to perform the cultivation of Spirulina maxima under temperate climate conditions in simply constructed, low cost reactors

19 Radioterapia ziarnicy złośliwej u dzieci w materiale I Zakładu Teleradioterapii Centrum

W latach 1986–1998 w I Zakładzie Radioterapii Centrum Onkologii w Warszawie leczono 97 dzieci z rozpoznaniem ziarnicy złośliwej, w wieku od 2 do 18 lat. Ponad połowa pacjentów (58%) była powyżej 10 roku życia. Obserwowano znaczną przewagę chłopców M.:F = 1,77. Przeważali pacjenci w I i w II stopniu zaawansowania klinicznego (63%) i bez objawów ogólnych (62%). W rozpoznaniu histopatologicznym najczęstsza była postać NS (50%) i MC (31%).Wszystkie dzieci otrzymały leczenie chemiczne przed napromienianiem. U 71 zastosowano program B-POPA, u 18 COPP/OPPA, u pozostałych 9 inne schematy leczenia. Pacjenci byli napromieniani na teren pierwotnie zajętych okolic węzłowych, promieniami telekobaltu-60. Stosowano dawki od 20 do 36 Gy, przeważnie 25 Gy (u 65%).Obecnie żyje 91 pacjentów, zmarło jedno dziecko, 5 stracono z obserwacji. Osiemdziesięciu pacjentówzyje żyje bez nawrotu choroby. U żadnego z pozostających w obserwacji dzieci nie stwierdzono póżnych powikłań po napromienianiu

Interesterificación de fosfatidilcolina de yema de huevo y aceites vegetales catalizada por lipasas

The incorporation of polyunsaturated fatty acids into the sn-1 position of egg-yolk phosphatidylcholine (PC) in the process of lipase-catalyzed interesterification was investigated. For this purpose plant oils containing these acids in the triacylglycerol (TAG) form were used as acyl donors and three commercially available immobilized lipases were examined as biocatalysts. In all the experiments the best results were obtained using Novozym 435. After 72 h of the reaction of PC with linseed oil the maximum incorporation of α-linolenic acid into PC was 34%. The result of this reaction was also a reduction in the n-6/n-3 ratio in egg-yolk PC from 24.5 to 0.7. The highest incorporation n-6 PUFAs into PC were obtained with evening primrose oil as the acyl donor, and in this case, 50.7% of n-6 PUFA as the sum of linoleic and γ-linolenic was achieved. The highest content of γ-linolenic acid in modified PC (7.3%) was achieved in the reaction of PC with borage oil.Se ha investigado la incorporación de ácidos grasos poliinsaturados en la posición sn-1 de fosfatidilcolina de yema de huevo (PC) en el proceso de interesterificación catalizado por lipasas. Para lograr este propósito, fueron examinados aceites vegetales que contienen estos ácidos en la forma de triacilgliceroles (TAG) como donadores de acilo y tres lipasas inmovilizadas disponibles comercialmente. En todos los experimentos los mejores resultados se obtuvieron para Novozym 435. La incorporación máxima de ácido α-linolénico en PC fue del 34% después de 72h de la reacción de PC con aceite de linaza. El resultado de esta reacción fue también la reducción de la relación de n-6/n-3 en PC de yema de huevo de 24.5 a 0.7. La incorporación más alta de n-6 PUFAs en PC se logró para el aceite de onagra como donador de acilo, en este caso se alcanzó el 50.7% de n-6 PUFA, como suma de los ácidos linoleico y γ-linolénico. El mayor contenido de ácido γ-linolénico en PC modificado (7.3%) se logró en la reacción de PC con aceite de borraja

Evaluation of acidogenesis products’ effect on biogas production performed with metagenomics and isotopic approaches

Background: During the acetogenic step of anaerobic digestion, the products of acidogenesis are oxidized to substrates for methanogenesis: hydrogen, carbon dioxide and acetate. Acetogenesis and methanogenesis are highly interconnected processes due to the syntrophic associations between acetogenic bacteria and hydrogenotrophic methanogens, allowing the whole process to become thermodynamically favorable. The aim of this study is to determine the influence of the dominant acidic products on the metabolic pathways of methane formation and to find a core microbiome and substrate-specific species in a mixed biogas-producing system. Results: Four methane-producing microbial communities were fed with artificial media having one dominant component, respectively, lactate, butyrate, propionate and acetate, for 896 days in 3.5-L Up-flow Anaerobic Sludge Blanket (UASB) bioreactors. All the microbial communities showed moderately different methane production and utilization of the substrates. Analyses of stable carbon isotope composition of the fermentation gas and the substrates showed differences in average values of δ13C(CH4) and δ13C(CO2) revealing that acetate and lactate strongly favored the acetotrophic pathway, while butyrate and propionate favored the hydrogenotrophic pathway of methane formation. Genome-centric metagenomic analysis recovered 234 Metagenome Assembled Genomes (MAGs), including 31 archaeal and 203 bacterial species, mostly unknown and uncultivable. MAGs accounted for 54%–67% of the entire microbial community (depending on the bioreactor) and evidenced that the microbiome is extremely complex in terms of the number of species. The core microbiome was composed of Methanothrix soehngenii (the most abundant), Methanoculleus sp., unknown Bacteroidales and Spirochaetaceae. Relative abundance analysis of all the samples revealed microbes having substrate preferences. Substrate-specific species were mostly unknown and not predominant in the microbial communities. Conclusions: In this experimental system, the dominant fermentation products subjected to methanogenesis moderately modified the final effect of bioreactor performance. At the molecular level, a different contribution of acetotrophic and hydrogenotrophic pathways for methane production, a very high level of new species recovered, and a moderate variability in microbial composition depending on substrate availability were evidenced. Propionate was not a factor ceasing methane production. All these findings are relevant because lactate, acetate, propionate and butyrate are the universal products of acidogenesis, regardless of feedstock