Biological Sciences Seminars

Production of 1,3-propanediol from glycerol under haloalkaline conditions

Daniel Roush

MS Candidate, Biological Sciences

Missouri S&T 

Monday, May 6, 2013

12:00 pm

Room 126, Schrenk Hall

Abstract:

With greater emphasis being placed on developing environmentally friendly technologies and chemicals, a shift has occurred in which old commodities have become new waste products. A prominent example of this shift has occurred with increased biodiesel production in which glycerol has gone from a high priced commodity to a cheap waste product. Finding ways of utilizing these waste products is imperative in assisting the transition from hydrocarbon dependence to biological innovation.  1,3-propandiol is a polymeric precursor that can be synthesized from glycerol by microorganisms, however crude glycerol from biodiesel production contains many contaminates leading to harsh growth conditions. Identifying organisms capable of surviving in these conditions creates an opportunity to reduce costs and bypass steps associated with neutralizing crude glycerol.  An organism has been identified, Halanaerobium hydrogeniformens, that can convert glycerol into 1,3-propanediol under haloalkaline conditions. Samples were grown over five days at pH 11 and at 7% (w/v) sodium chloride. Samples were amended with cobalamin to stimulate 1,3-propanediol production. HPLC analysis indicated statistically significant production of 1,3-propanediol . Bottles amended with 50 µg/L cobalamin had a significant increase in 1,3-propanediol production compared to glycerol-only samples Data indicated a 0.6mol/mol conversion rate for cobalamin amended samples, while glycerol-only samples had a conversion rate of 0.04mol/mol. 1,3-propanediol production from crude glycerol from biodiesel production was also examined.  By identifying and utilizing extremophilic bacteria in biotechnological applications, chemical processes can be developed that embrace extreme conditions and provide cost savings over traditional methods.

Emersion-Immersion cycles and the Fungal Communities on Leaf Litter in Streams

Kele Thrailkill

MS Candidate, Biological Sciences

Missouri S&T 

Monday, May 6, 2013

12:00 pm

Room 126, Schrenk Hall

Abstract:

Leaf litter is major source of energy for streams in deciduous forests. Fungi play a critical role by converting the leaves into nutritional material for the rest of the food web. These fungal communities can be affected by the leaf litter they are growing on becoming emersed and re-immersed due to pulse flow events. I used DGGE in tandem with clone libraries to assess the community structure of fungi on leaves from several sites with varying emersion-immersion over a 15 week period.  I also measured fungal biomass and microbial activity, which were closely related to each other throughout the sampling period and related to site immersion during the first sampling at 3 weeks.  Sites that underwent an emersion-immersion cycle had lower activity than immersed sites initially but similar rates later after communities had become established.  Community composition and diversity varied among samples based on immersion, watershed, and time.

The Geomicrobiology of a Sulfate-Reducing Bioreactor Treating Coal Generated Acid Mine Drainage

Dr Kelly Bender

Associate Professor, Department of Microbiology

Southern Illinois University 

Monday, April 29, 2013

12:00 pm

Room 126, Schrenk Hall

Abstract: Acid Mine Drainage (AMD) is a global problem of environmental and ecological concern. Oxidative dissolution of pyrite (FeS₂) from coal mining creates a self-perpetuating cycle of iron oxidation and acid generation. This cycle is accelerated by the activities of acidophilic microorganisms that are prevalent in AMD-generating ecosystems. Because microbial sulfate-reduction facilitates metal removal as well as alkalinity generation, passive flow sulfate-reducing bioreactors have been proposed as a possible remediation option. The geochemistry and microbial community of a bioreactor located outside of Carbondale, IL was assessed by chemical analyses and 16S rRNA and dsrA gene clone libraries. The results indicated that the treatment system was successful in both raising the pH of the AMD from 3.09 to 6.56 and in lowering the total iron level by 95.9%. While sulfate levels did decrease by 67.4%, the level post treatment (1153 mg/L) remained above recommended drinking water levels. Stimulation of biological sulfate reduction was indicated by a +2.60 ‰ increase in d³⁴S content of the remaining sulfate in the water post-treatment. Bacterial community analysis indicated that iron-oxidizing Betaproteobacteria dominated the pre-treated samples, while the post-treated water was dominated by sequences related to sulfur-oxidizing Epsilonproteobacteria and complex carbon degrading Bacteroidetes and Firmicutes phylums. DsrA analysis implied limited diversity in the sulfate-reducing population present in post-treated water. These results support the utility of sulfate-reducing bioreactors to treat AMD, but suggest modifications of the system are necessary to further stimulate sulfate-reducing bacteria. To test mixtures of substrates that result in optimal conditions for remediation of AMD by sulfate-reducing bioreactors, six in situ batch-scale reactors were constructed.  These reactors are currently being monitored using chemical, 16S rRNA gene pyrosequencing, and FISH analyses.

Broad-Spectrum Antibacterial Properties of Metal-Ion Doped Borate Bioactive Glasses for Clinical Applications

Megan Ottomeyer

Biological Sciences MS Candidate

Missouri S&T University 

Monday, April 22, 2013

12:00 pm

Room 126, Schrenk Hall

Abstract:  Bioactive glasses with antimicrobial properties can be implemented as coatings on medical devices and implants, as well as a treatment for tissue repair and prevention of common hospital-acquired infections such as MRSA. A borate-containing glass, B3, is also undergoing clinical trials to assess wound-healing properties. The sensitivities of various bacteria to B3, B3-Ag, B3-Ga, and B3-I bioactive glasses were tested. In addition, the mechanism of action for the glasses was studied by spectroscopic enzyme kinetics experiments, Live-Dead staining fluorescence microscopy, and luminescence assays using two gene fusion strains of Escherichia coli. It was found that gram-positive bacteria were more sensitive to all four glasses than gram negative bacteria, and that a single mechanism of action for the glasses is unlikely, as the rates of catalysis for metabolic enzymes as well as membrane permeability was altered after glass exposure.