Shining a Light on Wastewater Treatment with Microalgae.

Microalgae can produce biofuels, nutriceuticals, pigments and many other products, but commercialization has been limited by the cost of growing, harvesting and processing algal biomass. Nutrients, chiefly nitrogen and phosphorus, are a key cost for growing microalgae, but these nutrients are present in abundance in municipal wastewater where they pose environmental problems if not removed. This is not a traditional review article; rather, it is a fact-based set of suggestions that will have to be investigated by scientists and engineers.

Enhancement of Microbial Biodesulfurization via Genetic Engineering and Adaptive Evolution.

In previous work from our laboratories a synthetic gene encoding a peptide ("Sulpeptide 1" or "S1") with a high proportion of methionine and cysteine residues had been designed to act as a sulfur sink and was inserted into the dsz (desulfurization) operon of Rhodococcus erythropolis IGTS8. In the work described here this construct (dszAS1BC) and the intact dsz operon (dszABC) cloned into vector pRESX under control of the (Rhodococcus) kstD promoter were transformed into the desulfurization-negative strain CW25 of Rhodococcus qingshengii. The resulting strains (CW25[pRESX-dszABC] and CW25[pRESX-dszAS1BC]) were subjected to adaptive selection by repeated passages at log phase (up to 100 times) in minimal medium with dibenzothiophene (DBT) as sole sulfur source.

Biodesulfurization: a model system for microbial physiology research.

Biological desulfurization (biodesulfurization) of dibenzothiophene (DBT) by the 4S pathway is a model system for an enviromentally benign way to lower the sulfur content of petroleum. Despite a large amount of effort the efficiency of the 4S pathway is still too low for a commercial oil biodesulfurization process, but the 4S pathway could potentially be used now for commercial processes to produce surfactants, antibiotics, polythioesters and other chemicals and for the detoxification of some chemical warfare agents. Proteins containing disulfide bonds are resistant to temperature, pH, and solvents, but the production of disulfide-rich proteins in microbial hosts is challenging.

Isolation and characterization of an interactive culture of two Paenibacillus species with moderately thermophilic desulfurization ability.

Objective: To isolate and characterize novel thermophilic bacteria capable of biodesulfurization of petroleum.

Results: A culture containing two Paenibacillus spp. (denoted "32O-W" and "32O-Y") was isolated by repeated passage of a soil sample at up to 55 °C in medium containing dibenzothiophene (DBT) as sulfur source.

Characterization of the dszABC genes of Gordonia amicalis F.5.25.8 and identification of conserved protein and DNA sequences.

Gordonia amicalis F.5.25.

Microbial biocatalyst developments to upgrade fossil fuels.

Steady increases in the average sulfur content of petroleum and stricter environmental regulations concerning the sulfur content have promoted studies of bioprocessing to upgrade fossil fuels. Bioprocesses can potentially provide a solution to the need for improved and expanded fuel upgrading worldwide, because bioprocesses for fuel upgrading do not require hydrogen and produce far less carbon dioxide than thermochemical processes. Recent advances have demonstrated that biodesulfurization is capable of removing sulfur from hydrotreated diesel to yield a product with an ultra-low sulfur concentration that meets current environmental regulations.

Rapid detection and high-resolution discrimination of the genus Streptomyces based on 16S-23S rDNA spacer region and denaturing gradient gel electrophoresis.

As the leading source of antibiotics, Streptomyces species are the subject of widespread investigation. Many approaches have been tried to aid in the classification of Streptomyces isolates to the genus, species, and strain levels. Genetic methods are more rapid and convenient than classification methods based on phenotypic characteristics, but a method that is universal in detecting all Streptomyces yet selective in detecting only Streptomyces is needed.

Effect of aeration and agitation on growth rate of Thermus thermophilus in batch mode.

The growth kinetics of Thermus thermophilus HB27 was investigated in rich medium (Thermus medium) under batch cultivation at 65 degrees C in 3-l fermentors. The growth and oxygen consumption rates were highly dependent on the aeration and agitation rates. Volumetric mass transfer coefficient (K(L)a, h(-1)) and hence oxygen transfer rate (OTR, mol m (-3) h(-1)) into the fermentation broth increased with increased aeration and/or agitation rates.

New method to characterize microbial diversity using flow cytometry.

The majority of microorganisms have yet to be cultivated and represent a vast uncharacterized and untapped resource. Here, we report the utilization of a combination of flow cytometry, cultivation, and molecular genetics to develop new methodologies to access and characterize biodiversity in microbial samples. We demonstrate that fluorescent dyes and combinations of dyes can selectively stain portions of bacterial populations that can be isolated as sub-populations using fluorescence-activated cell sorting (FACS).

Heterologous gene expression in Thermus thermophilus: beta-galactosidase, dibenzothiophene monooxygenase, PNB carboxy esterase, 2-aminobiphenyl-2,3-diol dioxygenase, and chloramphenicol acetyl transferase.

Enzymes from thermophiles are preferred for industrial applications because they generally show improved tolerance to temperature, pressure, solvents, and pH as compared with enzymes from mesophiles. However, nearly all thermostable enzymes used in industrial applications or available commercially are produced as recombinant enzymes in mesophiles, typically Escherichia coli. The development of high-temperature bioprocesses, particularly those involving cofactor-requiring enzymes and/or multi-step enzymatic pathways, requires a thermophilic host.

Characterization of microbial communities in gas industry pipelines.

Culture-independent techniques, denaturing gradient gel electrophoresis (DGGE) analysis, and random cloning of 16S rRNA gene sequences amplified from community DNA were used to determine the diversity of microbial communities in gas industry pipelines. Samples obtained from natural gas pipelines were used directly for DNA extraction, inoculated into sulfate-reducing bacterium medium, or used to inoculate a reactor that simulated a natural gas pipeline environment. The variable V2-V3 (average size, 384 bp) and V3-V6 (average size, 648 bp) regions of bacterial and archaeal 16S rRNA genes, respectively, were amplified from genomic DNA isolated from nine natural gas pipeline samples and analyzed.

Isolation and characterization of Sphingomonas sp. GTIN11 capable of carbazole metabolism in petroleum.

A bacterial culture was isolated from a manufactured gas plant (MGP) soil based on its ability to metabolize the nitrogen-containing heterocycle carbazole. The culture was identified as a Sphingomonas sp. and was given the designation GTIN11.