Use of Local Raw Materials for the Production of Bacillus sphaericus Insecticide in Ghana

Locally available raw materials were used as fermentation media for the preparation of an effective bacterial insecticide of Bacillus sphaericus in Ghana. The choice of materials for media production was based on their availability, their cost and how well they supported growth and sporulation of the bacterium. The materials used were anchovy (Engraulis encrasicolus), spent grain from breweries, bambara beans (Vigna subterranea), sprout maize (Zea mays) and B. sphaericus strain IAB 881. The larvicidal activities of each final whole culture of the insecticides prepared were evaluated against third and fourth instar larvae of the mosquito species Culex quinquefasciatus. The levels of larvicidal activity exhibited by preparations using the raw materials were similar to those where the bacterium was cultured in a synthetic medium, with median lethal concentrations ranging from 0.30 10- 5 to 0.68 10-6. Cell counts were in the range 11 108 - 36 108 colony-forming units ml-1, and spore counts were between 29 107 and 61 107 ml-1.     

Kinetics of aggregation of αs1 -casein/ca2+ mixtures: charge and temperature effects

Time-dependent light-scattering studies have been made on mixtures of α_s1 -casein and Ca²⁺ at fixed temperature over a range of [Ca²⁺] and [α_s1 -casein], and also as functions of temperature- Measurements were also made of the extent of precipitate formation in the casein/Ca²⁺ mixtures, using centrifugation. The results are analysed in terms of a monomeroctamer equilibrium between calcium caseinate particles followed by a Smoluchowski aggregation in which only the octamers can participate. The equilibrium constant is dependent upon the charge on the protein/Ca²⁺ particles, and hence can be related to the extent of binding of Ca²⁺ to the α_s1 -casein. The Smoluchowski constant is likewise shown to be charge-dependent. The variation of the reaction rate with temperature can be ascribed solely to the changing charge of the α_s1 -casein/Ca²⁺ complex caused by changed binding of Ca²⁺ at different temperatures.     

Concomitant wastewater treatment with lipid and carotenoid production by the oleaginous yeast Rhodosporidium toruloides grown on brewery effluent enriched with sugarcane molasses and urea

In this study, secondary brewery wastewater (SBWW) supplemented with sugarcane molasses (SCM) was used for SBWW treatment with concomitant lipid and carotenoid production by the yeast Rhodosporidium toruloides NCYC 921. In order to improve the biomass production, ammonium sulfate, yeast extract and urea were tested as nitrogen sources. Urea was chosen as the best low-cost nitrogen source. A fed-batch cultivation was carried out with SBWW supplemented with 10 g L⁻¹ of sugarcane molasses as carbon source, and 2 g L⁻¹ of urea as nitrogen source. A maximum biomass concentration of 42.5 g L⁻¹ was obtained at t = 126.5 h and the maximum biomass productivity was 0.55 g L⁻¹ h⁻¹ at t = 48.25 h. The maximum lipid content was 29.9 % w/w (DCW) at t = 94 h of cultivation and the maximum carotenoid content was 0.23 mg g⁻¹ at 120 h of cultivation. Relatively to the SBWW treatment, after the batch phase, 45.8 % of total Kjeldahl nitrogen removal, 81.7 % of COD removal and 100 % of sugar consumption were observed. Flow cytometry analysis revealed that 27.27 % of the cells had injured membrane after the inoculation. This proportion was reduced to 10.37 % at the end of the cultivation, indicating that cells adapted to the growth conditions.     

Enhanced ethanol fermentation of brewery wastewater using the genetically modified strain <Emphasis Type="Italic">E. coli </Emphasis>KO11

We have used liquid waste obtained from a beer brewery process to produce ethanol. To increase the productivity, genetically modified organism, Escherichia coli KO11, was used for ethanol fermentation. Yeast was also used to produce ethanol from the same feed stock, and the ethanol production rates and resulting concentrations of sugars and ethanol were compared with those of KO11. In the experiments, first the raw wastewater was directly fermented using two strains with no saccharification enzymes added. Then, commercial enzymes, α-amylase, pectinase, or a combination of both, were used for simultaneous saccharification and fermentation, and the results were compared with those of the no-enzyme experiments for KO11 and yeast. Under the given conditions with or without the enzymes, yeast produced ethanol more rapidly than E. coli KO11, but the final ethanol concentrations were almost the same. For both yeast and KO11, the enzymes were observed to enhance the ethanol yields by 61–84% as compared to the fermentation without enzymes. The combination of the two enzymes increased ethanol production the most for the both strains. The advantages of using KO11 were not demonstrated clearly as compared to the yeast fermentation results.     

成熟厌氧颗粒污泥的结构及其特征*

厌氧序批式反应器〈AnaerobicSequencingBatchReactorASBR〉在处理啤酒废水过程中 ,能形成厌氧颗粒污泥。文中采用扫描电子显微镜和荧光显微镜技术对成熟厌氧颗粒污泥的结构及微生物群落等进行跟踪观察 ,结果显示 ,颗粒污泥结构复杂 ,细菌以微群落形式分布 ,其中产甲烷菌占一定比例。同时也探讨了厌氧颗粒污泥的形成机制。     

Alleviation of the effects of nitrogen limitation in high gravity worts through increased inoculation rates

Summary There are few inexpensive, practical methods to increase the usable nitrogen level in a substrate to be fermented to a potable alcohol product, but the provision of adequate assimilable nitrogen to a fermentation medium is critical for rapid and full wort attenuation. One practical solution to circumvent the problem may be to increase the inoculation rate to much higher than recommended levels. In this work, an increase in the pitching rate from 1.6×10⁷ cfu/ml to 8×10⁷ cfu/ml was shown to alleviate fermentation problems caused by nitrogen limitation. Attenuation and ethanol production rates became independent of the initial wort-free amino nitrogen (FAN) concentration, as did yeast viability and maximal yeast cell number. However, the final total cell mass was lower if the wort was nitrogen-deficient, regardless of the pitching rate. These cells were smaller and/or lighter and contained less protein at the end of fermentation. Such yeast could cause problems in subsequent fermentations if reuse of yeast (common in brewing) was considered.     

Traces of a possible Celtic brewery in Eberdingen-Hochdorf, Kreis Ludwigsburg, southwest Germany

A large number of weakly germinated hulled barley grains was found during archaeobotanical analyses from the early Celtic settlement excavations at Eberdingen-Hochdorf in southwest Germany (ca. 600 – 400 BC). These grains seem to represent deliberate germination, due to the purity of the find and its unusual archaeological context. The possibility of deliberate malting which could be connected with beer brewing is discussed. Recent germination and charring experiments show that the consistently weak traces of germination on the charred subfossil grains from Hochdorf are enough to indicate malted grains. A comparison of the archaeobotanical remains with the written and archaeological sources shows that evidence of beer brewing from excavations is very scarce. There is practically no clear proof of brewing, while written sources and indirect suggestions are abundant. Neither archaeological finds nor either written or iconographic sources give exact details about the prehistoric brewing technology of the early Celts. The archaeological finds from Hochdorf seem to be the result of deliberate malting of hulled barley for the purpose of Celtic beer brewing.