Generation Of Toxic Substances Research Articles

Bioconversion of Lignocellulosic Biomass into Bioethanol: A Sustainable Approach

Production of biofuel from Lignocellulosic biomass (LCB) reduces the energy dependency on fossil fuels. The process of manufacture does not have any adverse environmental impact. LCB is an abundant and promising renewable resource for long term biofuel supply. Bioethanol derived from LCB has the potential to meet the current energy demand, reduces greenhouse gases and supports rural economy. Cellulosic ethanol is one of the viable energy sources and therefore, it is considered as an alternative fuel. A lot of efforts have been made in the last decades on production of ethanol from cellulosic source as cost competitive with conventional fossil fuel. The production of bioethanol involves three steps: pretreatment, hydrolysis and fermentation. Pretreatment of LCB is usually done following physical, chemical or physicochemical process. Hydrolysis is carried out either chemically or enzymatically followed by microbial fermentation. However, involvement of costly equipment, high energy consumption and generation of toxic substances need to be evaluated. This drives the attention of scholars in the field towards alternative option for the development and optimization of biological methods of pretreatment, hydrolysis and fermentation. In this review we focus on recent developments of biological methods of pretreatment, hydrolysis and fermentation with respect to their advantages and limitations.

Improvement of Poultry Welfare and Production, in Chickens’ Farms, by Applying an Enzymatic Product

The poultry sector presents a positive growth trend in many countries, because of the world population raiser, which leads to an increase in the volume of waste and emissions generated. This means new management and treatment challenges [1]. Poultry industry waste includes a mixture of excrement (manure), bedding material (wood shavings, straw ...), food debris, dead birds, broken eggs, feathers, etc. It is commonly referred as a chicken manure. This chicken litter has a high value in nutrients (nitrogen, phosphorus and potassium), and has been used as an organic fertilizer, using techniques of direct dumping on land [2]. However, excessive application of this material can result in too high enrichment of water nutrients, resulting in eutrophication, spread of pathogens, and generation of toxic substances, air pollution and emissions of greenhouse gases [3].

Dispersion is essential in crop residue application

Background: Crop residue application can maintain soil fertility and sustain agriculture. However, the effects of residue application are unstable because of variable weather conditions and the residual effects of crop residue application. Furthermore, residue application often reduces crop yields. Therefore, I tried to clarify effective residue application factors in an environment which was has stable weather conditions and low residual effects. Methods: Majuro atoll, a coral sand atoll near the equator, was selected for the experiment site because of its stable weather and low residual effect of coral sand. A factorial design experiment using sweet corn was conducted based on the following four factors: fungi propagation before application, cutting residue into pieces, dispersion (or accumulation) of applied residue, and placement (on the surface or incorporation) with an equal amount of crop residue. The effects of each factors on the corn yields were evaluated using Cohen’s power analysis. Results: The dispersion showed the largest effect (1.2 in Cohen’s), which exceeded the effect of incorporation (0.7). The interaction of dispersion and incorporation showed a huge effect (4.9) on corn yield. Discussion: The effect of dispersion was not positive but it avoided the negative effects of residue clustering. Because, the toxicity of the plant residue and generation of toxic substances by anaerobic decomposition are widely known. Anaerobic decomposition occurs inside the residue clusters. However, dispersion reduced the toxicity by adsorption in soil and avoiding anaerobic decomposition. Furthermore, incorporation showed an interaction effect, but surface placement did not. Conclusion: The dispersion of crop residue enhanced the positive effect of crop residue incorporation by avoiding the toxicity from crop residue. This finding adds a new viewpoint for the controversy between conventional and conservation agriculture

Dispersion has a large effect (Cohen's d) on crop yield in crop residue application

Background: Crop residue application can maintain soil fertility and sustain agriculture. However, the effects of residue application are unstable because of variable weather conditions and the residual effects of crop residue application. Residue application often reduces crop yields. I tried to clarify effective residue application factors in an environment which was has stable weather conditions and low residual effects. Methods: Majuro atoll, a coral sand atoll near the equator, was selected for the experiment site because of its stable weather and low residual effect of coral sand. A factorial design experiment using sweet corn was conducted based on the following four factors: fungi propagation before application, cutting residue into pieces, dispersion (or accumulation) of applied residue, and placement (on the surface or incorporation) with an equal amount of crop residue. The effects of each factors on the corn yields were evaluated using Cohen’s power analysis. Results: The dispersion showed the largest effect (p = 0.045, Cohen’s d = 1.2), which exceeded the effect of incorporation (p = 0.223, Cohen’s d = 0.7). The interaction of dispersion and incorporation showed a huge effect on corn yield (p = 0.005, Cohen’s d = 4.9). Discussion: The effect of dispersion was not positive but it avoided the negative effects of residue clustering. The toxicity of the plant residue and generation of toxic substances by anaerobic decomposition are widely known. Anaerobic decomposition occurs inside the residue clusters. However, dispersion reduced the toxicity by adsorption in soil and avoiding anaerobic decomposition. Furthermore, incorporation showed an interaction effect, but surface placement did not. Conclusion: The dispersion of crop residue enhanced the positive effect of crop residue incorporation by avoiding the toxicity from crop residue. This finding adds a new viewpoint for the controversy between conventional and conservation agriculture.

Elementary and systemic views of the generation of toxic substances

The generation and utilisation of toxic side-products is discussed in this Editorial, part of a series celebrating the Twelve Principles of Green Chemistry.

Ultrasound-assisted post-packaging pasteurization of sausages

Ultrasound (US) is proposed to reduce temperature and accelerate the process of pasteurization of packaged hot dog sausages. They were pasteurized in an ultrasonic bath (25 kHz, 200 W) for 10.53 min at 74 °C with (US) and without ultrasound (WUS) and also with conventional pasteurization (CT, water bath at 82 °C, 16 min to reach 73 °C inside of sausages). The temperature was 3.9 °C higher inside of pasteurized sausages using US in comparison to WUS. Sausages were stored by 60 days and physico-chemical and microbiological parameters were evaluated. US treatment inhibited the growth of psychrotrophic and lactic bacteria, reduced the lipid oxidation and promoted little pH and texture modifications during storage, improving the pasteurization. However, no information are available about the possible generation of toxic substances after US processing and further investigations must be carried out before the industrial scale-up of the process. An improvement on the effect of pasteurization of packaged sausages could be obtained by the use of ultrasound, reducing the time and the temperature used in conventional process and improving the shelf life of product without changes in its physical and chemical characteristics. The adaptation of the proposed process is relatively simple to be performed in conventional equipment used in industry and has potential for continuous processing and scale up. Because no information are available about the possible generation of toxic substances after the US processing, further investigations must be carried out before the industrial scale-up of the process.

Methodology for pollution source reduction assessments of the manufacturing process chemistry in the US EPA's pre-manufacture notice reviews

The Office of Pollution Prevention and Toxics of the US Environmental Protection Agency (EPA) has initiated assessments of the pollution potential associated with the chemistry of chemical manufacturing processes in its review of pre-manufacture notices submitted by manufacturers of chemicals not on the Toxic Substances Control Act Inventory. The objectives of the assessments are to: (1) achieve pollution prevention by determining whether the process chemistry of a manufacturing process has significant raw material utilization inefficiencies, especially in terms of the generation of toxic substances in the waste streams, prior to the use of any control technology; (2) indicate, where possible, the causes for the inefficiencies and associated waste products; and (3) suggest possible approaches for reducing the use or generation of toxic substances. The rationale for such assessments is based on the idea that, as the use or generation of toxic substances is reduced or eliminated, the potential for exposure and releases, and therefore the risk, is correspondingly reduced. The methodology used in the assessments is described in this paper.

Influence of Processing on Nutrients in Foods

Considerable research effort has been devoted to the effect of processing on nutrients in foods. Yet only recently has a systematic approach been used to identify changes in processes which result in improved nutritional content of the product. The catalyst for this systematic approach has been the generation of kinetic data on the influence of environmental factors on the stability of nutrients which can then be used in process models. The effort to quantify reactions important in foods must continue for both nutrients and toxic constituents, but because of limited resources, we should conscientiously choose which environmental factors and which nutrients or toxic substances will be studied. The example of improving nutrient retention in canned foods by choice of time/temperature treatment and by changing geometry is used to illustrate the application of modeling. Additional research effort is warranted on the effect of water activity on nutrient stability, the generation of toxic substances during processing and the bioavailability of nutrients as influenced by processing.