Temperature and pH effect on glucose production from pretreated bagasse by a novel species of Citrobacter and other bacteria.

Cellulolytic bacteria that produce cellulases, which are active over a range of pH and temperatures, can be used to catalyze hydrolysis of pretreated lignocellulosic material. This is important in the production of second generation biofuels among other biotechnological applications. In this investigation, bacteria isolated from sugarcane bagasse were identified as strains of Enterobacter xiangfangensis, Serratia rubidaea, Klebsiella pneumoniae and a novel species of Citrobacter designated Citrobacter sp. UWIBGS10. The glucose production potential of these strains was studied on thermally and solvent pretreated sugarcane bagasse. This was performed at 24-hour intervals up to 168 hours in the range of pH 5-9 and temperature range 25-40 °C. Maximal concentrations of glucose for Citrobacter sp. UWIBGS10 occurred at pH 6 and 25 °C. For E. xiangfangensis, S. rubidaea, K. pneumoniae glucose concentrations were consistent across the pH and temperature ranges examined. From these results it could be concluded that the bacteria demonstrated ability for lignocellulolytic hydrolysis for the production of glucose and could be further explored for the characterization of commercial cellulolytic enzymes.

Review of ß-carboline alkaloids from the genus Aspidosperma.

Plants belonging to the genus Aspidosperma, a member of the family Apocynaceae, provide a rich source of ß-carboline alkaloids, which makes them potentially poisonous. However, some of these alkaloids possess antitumor and antimicrobial activity. The present review is a survey of the ß-carboline alkaloids and shows that they comprise of a diverse array of structural modifications.

Tirucallane, apotirucallane, and octanorapotirucallane triterpenes of Simarouba amara.

A chemical investigation of the bark of Simarouba amara, collected in Barbados, resulted in the isolation of six new triterpenes (3-8), in addition to two known compounds, 3-oxatirucalla-7, 24-dien-23-ol (1) and niloticin (2). Compound 3 is a tirucallane triterpene, while compounds 4-7 are apotirucallane derivatives containing an epsilon-lactone in ring A. Compounds 6 and 7 were obtained as a mixture that could not be separated, while compound 8 is an octanorapotirucallane derivative that lacks the C(8) side chain. The structures of all compounds were determined by interpretation of physical data.

Saponins from Furcraea selloa var. marginata.

Four steroidal saponins were isolated from the leaves of Furcraea selloa var. marginata. These included one furostanol saponin, furcreafurostatin (1), and three known spirostanol saponins, furcreastatin (3), yuccaloeside C (4) and cantalasaponin-1 (5). The 22-O-methyl ether (2) of furcreafurostatin (1) was also characterized. The structures were determined by using a combination of spectroscopic techniques.

Labdane diterpenes of Leonurus sibiricus.

Seven new labdane diterpenes, sibiricinones A-E (1-4, 6) and 15-epi-sibiricinones D and E (5 and 7), and the flavone genkwanin were isolated from the aerial parts of Leonurus sibiricus. Sibiricinone D (4) and 15-epi-sibiricinone D (5), and sibiricinone E (6) and 15-epi-sibiricinone E (7), respectively, were isolated as C-15 epimeric pairs. These secondary metabolites were identified on the basis of 1D and 2D NMR including (1)H-(1)H COSY, HSQC, and HMBC spectroscopic techniques. The stereochemical configurations of compounds 4-7 were assigned through 2D T-ROESY and selective NOE experiments.

Alpha-pyrones and a 2(5H)-furanone from Hyptis pectinata.

Three pyrones and a 2(5H)-furanone, designated pectinolides D-G, have been isolated from the dichloromethane extract of Hyptis pectinata. The metabolites were characterized on the basis of 1D and 2D NMR spectroscopic techniques. The pyrones were identified as 6S-[3S,6S-(diacetoxy)-5R-hydroxy-1Z-heptenyl]-5S-hydroxy-5,6-dihydro-2H-pyran-2-one (1)- pectinolide D, 6S-[3S,5R,6S-(triacetoxy)-1Z-heptenyl]-5S-acetoxy-5,6-dihydro-2H-pyran-2-one (2)- pectinolide E and 6S-[3S,5R,6S-(triacetoxy)-1Z-heptenyl]-5S-acetoxy-4R-methoxy-3,4,5,6-tetrahydro-4H pyran-2-one (3)- pectinolide F. The furanone was identified as [2'Z,5(1')Z] 5-(4'S,6'R,7'S-triacetoxy-2-octenylidene)-2(5H)-furanone (4)-pectinolide G.

Cassane diterpenoids of Caesalpinia pulcherrima.

Five new cassane diterpenoids (1-5) were isolated from the roots of Caesalpinia pulcherrima, along with the known isovouacapenol C (6), pulcherrimin A (11), and 6beta-cinnamoyl-7beta-hydroxyvouacapen-5alpha-ol (12). Compounds 3-5 possess the alpha,beta-butenolide moiety, whereas compounds 1 and 2 contain a more usual 2,3-disubstituted furan unit. Compounds 7 and 8 were derived from hydrolysis of 6, while 9 and 10 were derived from acetylation and oxidation of 6, respectively. The (1)H and (13)C NMR spectra of all compounds were completely assigned using a combination of 2D NMR experiments, including (1)H-(1)H COSY, HSQC, HMBC, and T-ROESY sequences.

New cembrane diterpenes of the marine octocoral Eunicea tourniforti from the eastern Caribbean.

An investigation of the Caribbean octocoral Eunicea tourniforti collected along the southwest coast of Barbados afforded four new cembrane diterpenes, 1, 2, 4, and 5, along with the known cembranolide 3. The structures of all metabolites were determined by spectroscopic methods. Seasonal effects on the secondary metabolite content of the specimens collected were also observed.