A novel downstream process for 1,3-propanediol from glycerol-based fermentation.

In this paper, a downstream process for purification of 1,3-propanediol from glycerol-based fermentation broth was investigated. The purification of 1,3-propanediol from fermentation broth was achieved by a process combining microfiltration, charcoal treatment, vacuum distillation, and silica gel chromatography. The broth was first filtered through hollow fiber cartridge, wherein 98.7% of biomass was removed. Soluble proteins and other color impurities in the broth were removed by the use of activated charcoal at optimal concentration of 30 g l(-1) where the soluble proteins in the broth decreased to 0.1 g l(-1) (96.0% protein loss). The obtained broth when concentrated by vacuum distillation resulted in the crystallization of inorganic salts. Subsequently, 1,3-propanediol was purified by gradient chromatography using silica gel as a stationary phase and mixture of chloroform and methanol as a mobile phase. Finally, with the optimal flow rate of 10 ml min(-1) and loading amount of 80 ml, the yield of 1,3-propanediol achieved was 89%. The overall yield of 1,3-propanediol using the proposed procedure was 75.47%. The developed method was found to be a simple, rapid, and efficient procedure for the purification of 1,3-propanediol from fermentation broth.

ent-Kaurene diterpenoids from Blepharispermum hirtum.

The twigs and leaves of Blepharispermum hirtum Oliver (Asteraceae) were investigated for their larvicidal and antimicrobial activity. Fractionation of the extracts of the twigs, directed by brine shrimp test and antibacterial activities, led to the isolation of compounds 1-4; two of which are new ent-kaurene diterpenoids, blepharispins A and B (1 and 2, resp.). The structures of compounds 1 and 2 were established from spectral data. The absolute configuration at C(15) in 1 was inferred from Mosher ester analysis and relative configurations were suggested by a NOESY experiment. Compound 4 was significantly larvicidal to newly hatched naupleii of Artemia salina L. (BST LC(50)=1.3 (3.7-0.0) microg/ml), but the blepharispins were not (BST LC(50) > 500 microg/ml). Nevertheless, compound 1 inhibited the growth of Staphylococcus aureus and Bacillus subtilis at a MIC value of 62.5 microg/ml. The significance of the bioactivity results and the presence of ent-kaurene diterpenoids in B. hirtum are discussed from biosynthetic and local utilization viewpoints.

Identification of the chemotypes of Ocimum forskolei and Ocimum basilicum by NMR spectroscopy.

The chemotypes of Ocimum forskolei Benth and Ocimum basilicum L. growing wild in Oman have been established by (13)C-NMR analyses of the vegetative and floral oils of the plants. The chemotypes, estragole for O. forskolei and linalool for O. basilicum, suggested by (13)C-NMR fingerprinting were also confirmed by GC-FID and GC/MS analyses. The oil of O. forskolei demonstrated better activities against bacteria and dermatophytes. The significance of the presence of estragole and linalool in the volatile oils of plants whose fragrances are traditionally inhaled, added to food, or rubbed on the skin are discussed.

Production of phenylacetic acid derivatives and 4-epiradicinol in culture by Curvularia lunata.

Phenylacetic acid derivatives, methyl 2-acetyl-3,5-dihydroxyphenylacetate (1) and methyl 2-acetyl-5-hydroxy-3-methoxyphenylacetate (3); curvulin or ethyl 2-acetyl-3,5-dihydroxyphenylacetate (4), a known metabolite of Curvularia siddiqui, and 4-epiradicinol (5) have been isolated from the culture mycelia of Curvularia lunata grown on YMG, a medium consisting of yeast, malt extract and glucose. Compounds 1, 3 and 4 lack antimicrobial and antioxidant activity, but 4-epiradicinol (5) inhibited the growth of Escherichia coli, Staphylococcus aureus, Salmonella choleraesuis and Bacillus subtilis. The structures of compounds 1, 3-5 were determined by analyses of IR, MS, 1D and 2D NMR data, assisted by chemical shift comparison to related and model compounds. The relative stereochemistry of the vicinal diol in 5 was determined from the 1H NMR signals for the methyl protons of the resulting cyclic acetonide prepared from 5.

Chemical composition, antibacterial and antifungal activities of the essential oil of Haplophyllum tuberculatum from Oman.

The chemical composition of the essential oil of Haplophyllum tuberculatum (Forsskal) A. Juss (Rutaceae) was analyzed by gas chromatography-mass spectral (GC-MS) and 13C NMR spectroscopy. Thirty compounds, constituting about 99.7% of the total oil, were identified. The most abundant oil components are beta-phellandrene (23.3%), limonene (12.6%), (Z)-beta-ocimene (12.3%), beta-caryophyllene (11.6%), myrcene (11.3%), and alpha-phellandrene (10.9%). Ten microlitres (25 mg) of pure oil partially inhibited the growth of Escherichia coli, Salmonella choleraesuis, and Bacillus subtilis to the same extent as 0.10 microg of gentamycin sulfate. The oil also affected the mycelial growth of Curvularia lunata and Fusarium oxysporium in a dose-dependent manner but had no effect on the germination of their spores.

New sesquiterpenes from Pluchea arabica.

Two new sesquiterpenes, godotol A (1) and godotol B (2), were isolated from Pluchea arabica. Their structures were determined by analysis of NMR data. The absolute configurations of 1 and 2 were established by Mosher ester methodology. The godotols displayed weak activity against bacteria and the brine shrimp larvae. They were also inactive in the DPPH antioxidant assay.