The Use of a Fractional Factorial Design to Determine the Factors That Impact 1,3-Propanediol Production from Glycerol by Halanaerobium Hydrogeniformans

In recent years, biodiesel, a substitute for fossil fuels, has led to the excessive production of crude glycerol. The resulting crude glycerol can possess a high concentration of salts and an alkaline pH. Moreover, current crude glycerol purification methods are expensive, rendering this former commodity a waste product. However, Halanaerobium hydrogeniformans, a haloalkaliphilic bacterium, possesses the metabolic capability to convert glycerol into 1,3-propanediol, a valuable commodity compound, without the need for salt dilution or adjusting pH when grown on this waste. Experiments were performed with different combinations of 24 medium components to determine their impact on the production of 1,3-propanediol by using a fractional factorial design. Tested medium components were selected based on data from the organism\u27s genome. Analysis of HPLC data revealed enhanced production of 1,3-propanediol with additional glycerol, pH, vitamin B12, ammonium ions, sodium sulfide, cysteine, iron, and cobalt. However, other selected components; nitrate ions, phosphate ions, sulfate ions, sodium:potassium ratio, chloride, calcium, magnesium, silicon, manganese, zinc, borate, nickel, molybdenum, tungstate, copper and aluminum, did not enhance 1,3-propanediol production. The use of a fractional factorial design enabled the quick and efficient assessment of the impact of 24 different medium components on 1,3-propanediol production from glycerol from a haloalkaliphilic bacterium

Conversion of Glycerol to 1,3-propanediol under Haloalkaline Conditions

A method of producing 1,3-propanediol. The method comprises fermenting a haloalkaliphilic species of Halanaerobium with a source of glycerol into 1,3-propanediol, at a pH of greater than about 10 and at a salt concentration of greater than about 5% w/v. Furthermore, with supplementation of vitamin B12, the yield of 1,3-propanediol to glycerol can be increased

A Streamlined Strategy for Biohydrogen Production with Halanaerobium hydrogeniformans, an Alkaliphilic Bacterium

Biofuels are anticipated to enable a shift from fossil fuels for renewable transportation and manufacturing fuels, with biohydrogen considered attractive since it could offer the largest reduction of global carbon budgets. Currently, lignocellulosic biohydrogen production remains inefficient with pretreatments that are heavily fossil fuel-dependent. However, bacteria using alkali-treated biomass could streamline biofuel production while reducing costs and fossil fuel needs. An alkaliphilic bacterium, Halanaerobium hydrogeniformans, is described that is capable of biohydrogen production at levels rivaling neutrophilic strains, but at pH 11 and hypersaline conditions. H. hydrogeniformans ferments a variety of 5- and 6-carbon sugars derived from hemicellulose and cellulose including cellobiose, and forms the end products hydrogen, acetate, and formate. Further, it can also produce biohydrogen from switchgrass and straw pretreated at temperatures far lower than any previously reported and in solutions compatible with growth. Hence, this bacterium can potentially increase the efficiency and efficacy of biohydrogen production from renewable biomass resources

Comparison of Stirred and Immobilized Cell Reactors For Ethanol Production

Biomass can be converted to sugars by hydrolysis with enzymes or mineral acids. These sugars can be converted into a number of chemical intermediates in biological reactors. Biological reactions are generally slow and selection of the most efficient reactor is important in these applications. Immobilized cell reactors allow high cell densities and high throughput by attaching microorganisms to a fixed support. This paper compares the rate of production of ethanol from glucose by Saccharomyces Cerevisiae in a packed column and a stirred reactor. Continuous stirred reactor studies showed a washout rate of .27 hr-1. The optimum rate of alcohol production of 1.75 g/l-hr occurred at a dilution rate of .182 hr-1. In a 36 immobilized cell reactor, rates were found to be 7.4 g/l-hr, or about 4.2 times better than the stirred reactor. Sustained periods of operation of this type column are possible by removal of cell overgrowth with a gas purge. Immobilized cell reactors should also be more stable and should require lower power input than the mixed reactor

Ethanol Production In An Immobilized‐cell Reactor

Biomass can be converted to sugars by hydrolysis with enzymes or mineral acids. These sugars can be converted into a number of chemical intermediates in biological reactors. Biological reactions are generally slow and selection of the most efficient reactor is important in these applications. Immobilized‐cell reactors allow high cell densities and high throughput by attaching the microorganisms to a fixed support. This paper examines the rate of production of ethanol from glucose by Saccharomyces cerevisia in a packed column. These rates are compared with those for the same reaction in a stirred reactor. Copyright © 1980 John Wiley & Sons, Inc

Ultrasonically Initiated Free Radical Catalyzed Polymerization: The Poly(methyl Methacrylate) Emulsion System

In our continued work with the ultrasonically initiated free radical polymerization of olefins, we have included experiments for the emulsions polymerization of methyl methacrylate. We have shown that polymerization can be initiated in emulsions containing monomer and a special initiator with intense ultrasound. The weight average molecular weight of the Poly(methyl methacrylate) varies from 1,100, 000 to 1,700,000 g/mol and the conversion for the polymerization is up to 70%. Variations of the polymerization rate with time vs the amount of initiator are explained by a simple reaction mechanism

A Graphical Representation: For the Fugacity of a Pure Substance

A graphical representation of the mathematical definitions that explains the relationship between fugacity and Gibbs energy for a pure substance has been discussed. The PG diagram shows that the solid/liquid and vapor/liquid coexistence curves would intersect at the triple point (83.8 K and 0.689 bars). The Gibbs energy of a substance behaving as an ideal gas can be determined at any temperature and pressure provided that the absolute (or standard) entropy of the ideal gas is known at some reference state. The residual Gibbs energy at constant pressure is the difference between the Gibbs energy of the system and the Gibbs energy of a system of the same chemical composition and at the same temperature and pressure but behaving as an ideal gas. The fugacity of a pure substance at a temperature and pressure is the pressure at which the substance behaving as an ideal gas at the same temperature has the same Gibbs energy as the system

Evaluation of Computer-Based Assessment Methods for Engineering Courses

Several computer-based assessment methods have been used in chemical engineering classes at the University of Missouri-Rolla. This experience provides the basis for an evaluation of the technology and human factors involved in the application of these methods. From the student\u27s perspective, the major strength of computer-based assessments is the instantaneous feedback that is provided. From the instructor\u27s perspective, the major strengths are twofold: 1) rapid grading and 2) individualized assessments. The major drawbacks for the students are the loss of partial credit and the insecurity associated with working in a virtual environment. Faculty find that the time required to construct effective computer-based assessments is much greater than that for paper-based assessments. Unfortunately, the increase in construction time can be greater than the reduction in grading time. With the current technology, it is extremely difficult to develop large, multi-step problems requiring problem analysis and solution synthesis skills without leading the student to the answer. This, of course, defeats the purpose of the assessment for this type of problem

Biological Production Of Methane From Energy Crops

Laboratory studies at the University of Missouri‐Rolla have demonstrated the feasibility of producing methane by anaerobic digestion of various of crop materials, such as grasses and corn stalks. These studies indicate that up to 6.0 f3methane are produced/b crop material destroyed. Preliminary design and economic studies of a large methane plant show that the reactors represent the largest cost item and that efforts should be concentrated on defining reaction kinetics and reactor design. A process to produce 50 M̄ f3methane/day is described, and the preliminary design and economics are analyzed. Copyright © 1979 John Wiley & Sons, Inc