Plastics with oxo-biodegradable additives, like the Symphony materials, require oxygen to initialize degradation, making them possible solutions to plastic litter problems. The analogy of the fallen leaf has been used to explain how we might view littered oxo-degradable plastics. Leaves on the forest floor may take years to biodegrade, but they do degrade. Likewise, oxo-biodegradable plastic products are said to degrade in a similar manner when, unfortunately and inevitably, they become litter. Along with ASTM and other related standards for determining biodegradability, the Plastics Environmental Council is developing a landfill-biodegradability standard specification over the next couple of years. This is perhaps in response to incidents like the recent California lawsuit for removing claimed-to-be-biodegradable bottles from store shelves, with the argument that the bottles are not truly “biodegradable” in the way the word would be interpreted by consumers. The PEC’s member companies stand particularly to benefit from a biodegradability certification or rating system for their materials and products, but this is still at least another step in the right direction.

Waste Storage Area to maintain favorable conditions for the anaerobic bacteria. By enhancing reductive dechlorination (keeping the bacteria happy), solvent concentrations at the infusion wells were reduced by 93% within six months of startup. Hydrogen gas inFusion applications work well in combination with electron donors such as emulsified vegetable oils (EVO) and soluble substrates. Hydrogen gas inFusion can be used to provide supplemental hydrogen electron donor to recirculation water and precondition waters used for bioaugmentation cultures. inFusion gPRO® systems can also be used to produce hydrogen enriched chase water.

Piezophilic microorganisms, which are defined as "pressure-loving" microorganisms, are isolated and characterized from high pressure environments. They grow better at high-hydrostatic pressures than at atmospheric pressures, and only exist at deeper water column environments, particularly in the deep-sea bottoms. Therefore, piezophilic microorganisms are typical deep-sea microorganisms that are well adapted to deep-sea pressure and temperature conditions. These microorganisms have special strategies for surviving in such extreme environments, where gene expression and enzyme activities could be controlled by pressure. Studies on adaptations to high pressure environments have recently been studied in detail, and the mechanisms involved are being elucidated. In this chapter, the distribution, taxonomy, cultivation and molecular characters of piezophiles are described.

Hydrocarbons are the major representatives of non-metal pollutants found in many contaminated soils by natural or industrial and social activities. Their removal from polluted environmental niches depends to a great extent on microbial degradation, which can also be applied on several technological applications. The extended microbial diversity in soil has served as a rich source for the isolation of efficient PAH-degrading strains. Bacterial isolates with the ability to use PAHs as an alternative source of carbon and energy facilitate their mineralisation to harmless products. Culture-based approaches have resulted in the isolation of a range of soil hydrocarbon-degrading bacteria, which primarily are members of different subdivisions of Proteobacteria as well as of the high G+C Gram-positive bacteria. Generally, in polluted-soils Gram-negative bacteria such as Pseudomonas, Burkholderia and Sphingomonas seem to degrade preferentially lower molecular weight PAHs such as naphthalene and phenanthrene, while Gram-positive isolates are more specialized in the degradation of high molecular weight PAHs such as pyrene.

Bioremediation uses microorganisms to remove, detoxify, or immobilize pollutants, and does not require addition of harmful chemicals. Bioremediation is particularly suitable for large areas where contaminant concentrations are relatively low and the hydrology of the soil does not support an aggressive chemical remediation strategy. In the last few years, researchers have described the mechanisms of bioremediation for numerous priority pollutants, including chlorinated hydrocarbons, polyaromatic hydrocarbons, and heavy metals. However, most studies published to date have dealt with planktonic cultures grown under controlled laboratory conditions. Microorganisms in the environment occur mostly as biofilms, whose development is encouraged by the presence of solid surfaces and the limited amounts of organic carbon. Therefore, optimization of bioremediation processes in the field requires a thorough knowledge of biofilm structure, dynamic, and interaction with pollutants and other environmental factors.

"Biodegradable products are not necessarily more environmentally friendly when disposed in landfills" Biodegradable materials, such as disposable cups and utensils, are broken down in landfills by microorganisms that then produce methane. Methane can be a valuable energy source when captured, but is a potent greenhouse gas when released into the atmosphere. This problem may be exacerbated by the rate at which these human-made biodegradable materials break down. Federal Trade Commission (FTC) guidelines call for products marked as "biodegradable" to decompose within "a reasonably short period of time" after disposal. But such rapid degradation may actually be environmentally harmful, because federal regulations do not require landfills that collect methane to install gas collection systems for at least two years after the waste is buried. If materials break down and release methane quickly, much of that methane will likely be emitted before the collection technology is installed. This means less potential fuel for energy use, and more greenhouse gas emissions.

Landfills receive a wide variety of solid waste, and that waste generally starts out with a fairly low pH level," says Dr. Francis de los Reyes. "The low pH level makes it difficult for most methanogens -- methane-producing organisms -- to survive due to the mechanism that raises the pH level in landfills, fostering the growth of methanogens. M. barkeri consumes the acids in its environment, producing methane and increasing the pH levels in its immediate area. This, in turn, makes that area more amenable for other methanogens