Butanol production from wheat straw hydrolysate using <Emphasis Type="Italic">Clostridium beijerinckii</Emphasis>

In these studies, butanol (acetone butanol ethanol or ABE) was produced from wheat straw hydrolysate (WSH) in batch cultures using Clostridium beijerinckii P260. In control fermentation 48.9 g L⁻¹ glucose (initial sugar 62.0 g L⁻¹) was used to produce 20.1 g L⁻¹ ABE with a productivity and yield of 0.28 g L⁻¹ h⁻¹ and 0.41, respectively. In a similar experiment where WSH (60.2 g L⁻¹ total sugars obtained from hydrolysis of 86 g L⁻¹ wheat straw) was used, the culture produced 25.0 g L⁻¹ ABE with a productivity and yield of 0.60 g L⁻¹ h⁻¹ and 0.42, respectively. These results are superior to the control experiment and productivity was improved by 214%. When WSH was supplemented with 35 g L⁻¹ glucose, a reactor productivity was improved to 0.63 g L⁻¹ h⁻¹ with a yield of 0.42. In this case, ABE concentration in the broth was 28.2 g L⁻¹. When WSH was supplemented with 60 g L⁻¹ glucose, the resultant medium containing 128.3 g L⁻¹ sugars was successfully fermented (due to product removal) to produce 47.6 g L⁻¹ ABE, and the culture utilized all the sugars (glucose, xylose, arabinose, galactose, and mannose). These results demonstrate that C. beijerinckii P260 has excellent capacity to convert biomass derived sugars to solvents and can produce over 28 g L⁻¹ (in one case 41.7 g L⁻¹ from glucose) ABE from WSH. Medium containing 250 g L⁻¹ glucose resulted in no growth and no ABE production. Mixtures containing WSH + 140 g L⁻¹ glucose (total sugar approximately 200 g L⁻¹) showed poor growth and poor ABE production. Mention of trade names or commercial products in this article is solely for the purpose of providing scientific information and does not imply recommendation or endorsement by the United States Department of Agriculture.     

Culture of transgenic Drosophila melanogaster Schneider 2 cells in serum-free media based on TC100 basal medium

Requirements of eliminating animal proteins from cell culture have intensified in recent years, with the pressure of regulatory agencies related to biopharmaceuticals production. In this work, the substitution of fetal bovine serum by yeastolate and a soy hydrolysate (Hy Soy) for the culture of Drosophila melanogaster Schneider 2 cells transfected for the production of rabies virus G glycoprotein was evaluated. TC100 supplemented with glucose, glutamine, lipid emulsion and Pluronic F68 was employed as basal medium. Results show that yeastolate was more efficient on cell growth stimulation than Hy Soy. Cells adapted in medium formulation supplemented with 3 g/L yeastolate, 1% lipid emulsion, 10 g/L glucose, 3.5 g/L glutamine and 0.1% Pluronic F68 attained a maximum concentration of 10.7 x 10(6) cells/mL, with the expression of 9.4 ng/mL G glycoprotein.     

水淹生境下秋华柳对Cd污染土壤微生物数量及酶活性的影响

三峡库区消落带面临水淹及Cd污染双重胁迫,为探究秋华柳(Salix variegata Franch.)在水淹条件下对Cd污染土壤的修复能力,以秋华柳扦插苗为试验材料,设置正常供水(CK)和水淹组(FL)两个水分处理方式,4个Cd浓度梯度:对照组(0mg/kg)、低浓度(0.5mg/kg)、中浓度(2mg/kg)及高浓度(10mg/kg),分别对处理60 d和120 d的土壤微生物数量及酶活性变化特征进行研究。试验结果表明:(1)Cd浓度处理均未显著影响土壤微生物数量(P0.05),水淹显著降低处理60 d土壤细菌数、真菌数及处理120 d的土壤放线菌数及真菌数(P0.05)。(2)种植秋华柳显著提高处理60 d土壤细菌数量(P0.05),对土壤放线菌、真菌数量也有一定提升。(3)Cd浓度处理显著影响处理60 d土壤磷酸酶活性及处理120 d脲酶活性(P0.05),水淹显著降低处理60 d土壤磷酸酶活性及处理120 d脲酶、蔗糖酶和磷酸酶活性(P0.05)。(4)正常供水及水淹条件下,种植秋华柳对土壤酶活均有一定改善作用。种植秋华柳显著提高了处理60 d土壤磷酸酶活性以及处理120 d脲酶和蔗糖酶活性(P0.05)。研究结果表明:水淹生境中,秋华柳对Cd污染土壤微生物数量及酶活性具有改善作用,在Cd污染土壤修复方面有一定应用前景。     

Growth of Lactobacillus plantarum in media containing hydrolysates of fish viscera

AIMS: To compare growth of Lactobacillus plantarum on media containing hydrolysates (peptones) from cod viscera with growth on commercial media. METHODS AND RESULTS: Growth of Lact. plantarum on various fish peptones and commercial peptones/extracts was evaluated using both a Bioscreen apparatus (microtiter plates, no pH control) and fermentors (with pH control). Generally, the performance of the fish peptones was good and only beaten by the performance of yeast extract. Replacement of the 22 g l(-1) complex nitrogen source in standard MRS medium with only 5 g l(-1) fish peptone reduced the biomass yield with only 10%, whereas replacement with a mixture of 2.5 g l(-1) fish peptone and 2.5 g l(-1) yeast extract increased the biomass yield by 10%. CONCLUSIONS: Peptones derived from cod viscera support excellent growth of Lact. plantarum. SIGNIFICANCE AND IMPACT OF THE STUDY: We show that peptones derived from cod viscera are promising constituents of growth media for fastidious food bacteria such as lactobacilli. Media containing these peptones show excellent performance while problems associated with the use of meat-derived peptones (BSE, kosher status) or plant-derived peptones (genetically modified organisms) are avoided.     

Regioselective enzymatic acylation of ribavirin to give potential multifunctional derivatives

Lipase-catalyzed synthesis of potential multifunctional ribavirin derivatives was performed in acetone. Divinyl dicarboxylates with different chain lengths (C₄, C₆, C₉, C₁₀) were used as acyl donors and the reactions were catalyzed by lipase immobilized on acrylic resin from Candida antarctica (CAL-B). Ribavirin was regioselectivly acylated at the primary hydroxyl groups and the corresponding vinyl esters (C₄, C₆, C₉, C₁₀) were prepared in respective yields of 48%, 65%, 54%, 55%.     

Oxidative stress and antioxidant content in Chlorella vulgaris after exposure to ultraviolet-B radiation

Growth of Chlorella vulgaris was measured in cultures irradiated with 0, 0.8, 2.0 and 4.4 kJ m² UV-B. Growth expressed as chlorophyll content, declined significantly with increased UV-B dose. Ultraviolet-B irradiated cultures in log phase of growth showed a 284% increase in oxygen radical generation and a 145% increase in lipid peroxidation compared with unirradiated cultures, whereas cultures in the stationary growth phase showed no significant changes in these parameters. The activities of superoxide dismutase and catalase increased by 40 and 500%, respectively, after exposure to a UV-B dose of 4.4 kJ m⁻². Contents of the lipophilic antioxidants α-tocopherol and β-carotene increased by 180 and 63 amol cell⁻¹ respectively, between log and stationary phases in unirradiated cultures; but in UV-B-irradiated cultures these increases were significantly depressed. Photoreducing capacities of chloroplasts were decreased following UV-B irradiation of both isolated chloroplasts and those isolated from irradiated algae. Cells exposed to UV-B exhibited increased size and starch accumulation. These results suggest that oxidative stress conditions related to UV-B exposure trigger an antioxidant response that includes an increase in the activity of the antioxidant enzymes (superoxide dismutase and catalase).     

Soy-based medium for ethanol production byEscherichia coli KO11

An optimized soy-based medium was developed for ethanol production byEscherichia coli KO11. The medium consists of mineral salts, vitamins, crude enzymatic hydrolysate of soy and fermentable sugar. Ethanol produced after 24 h was used as an endpoint in bioassays to optimize hydrolysate preparation. Although longer fermentation times were required with soy medium than with LB medium, similar final ethanol concentrations were achieved (44–45 g ethanol L^–1 from 100 g glucose L^–1). The cost of materials for soy medium (excluding sugar) was estimated to be $0.003 L^–1 broth, $0.006 L^–1 ethanol.