Bioremediation and Environmental Biotechnology

Alba, Jayson, Monteverde, Omapoy, Villanueva

IntroductionEnvironmental biotechnology is the branch of biotechnology that addresses environmental problems, such as the removal of pollution, renewable energy generation or biomass production, by exploiting biological processes.

Figure 1 Photovoltaic panels Figure 2 Machine used in the electricity generation from digitally printed cyanobacteria

Introduction

• Environmental biotechnology inherits its origins with Charles Darwin's On the Origin of Species by Means of Natural Selection, where neo-Darwinian thought sees the mix of natural selection and mutation as the driving factor for biotechnology. The first patented efforts related to environmental biotechnology happened in 1982, where oil-eating microbes are commercially deployed.

• It integrates with current manufacturing processes to minimize the harmful output or residuals of the products. Environmental biotechnologists optimize biological processes by using organisms as is, forcing changes in growth through environmental factors, or genetically modifying the organisms.

Applications of environmental biotechnologyBiomarkers

• These refer to a biological measure of a biological state.

• They gives a response to a chemical that helps to measure the level of exposure or damage there is from certain substances found from pollution.

• They can help determine what approach to take in trying to recover an environment that is plagued with pollution or has been exposed to harmful substances.

• In medicine, biomarkers are useful in a number of ways, including measuring the progress of disease and evaluating the most effective therapeutic regimes for a particular cancer type, and establishing long-term susceptibility to cancer or its recurrence.

Applications of environmental biotechnologyBioenergy

• This refers to energy coming from organic matter. Examples of organic matter being used are wood, residues from agriculture or forestry, and fumes from landfills.

• It is usually used in the industrial, domestic, and space sectors and can help reduce greenhouse gas emissions. (It actually produces the same amount of carbon dioxide, but every time a new plant grows, carbon dioxide is being removed from the atmosphere.)

• Examples

• Biofuels converting biomass into liquid fuels for transportation.

• Biopower burning biomass directly, or converting it into a gaseous fuel or oil generating electricity

• Bioproducts converting biomass into chemicals for making products that are usually made of petroleum

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Applications of environmental biotechnologyBiotransformation

• This refers to the conversion of chemical substances in a biological environment into another and is usually used in the manufacturing.

• Example (Biodegradation)

• The disintegration of materials by bacteria, fungi, or other biological means.

• It is done to recycle waste so that the elements in them can be used again.

• Compounds that inhibit biodegradation are often added to automobile antifreeze solutions, aircraft deicer formulations, and other products to preserve the original qualities of the product.

• Important variables include temperature and moisture. Microorganisms also need energy, carbon, nitrogen, oxygen, phosphorus, sulfur, calcium, magnesium, and several metals to grow and reproduce.

Recent developments“Glowing bacteria to detect buried landmines”

Background

The major technical challenge in clearing minefields is detecting the mines. There is an estimated 110 million land mines in the ground right now. According to the International Campaign to Ban Landmines network, more than 4,200 people (42% of which are children), have been falling victim to landmines annually.

Breakthrough

Researchers from the Hebrew University of Jerusalem have presented a functional system combining lasers and bacteria to map landmines and unexploded ordinance. Based on observation, all landmines leak minute quantities of explosive vapors. They engineered live bacteria that emit a fluorescent signal when it comes into contact with these vapors. It can then be recorded and quantified from a remote location.

Criticism, issues, and concernsResearch in the field is relatively new

• Remediating the contaminated/pollution-rich environment is a need, but prefer to think it as a problem that should not exist on the first place.

• Multidisciplinary nature causes immense amount of public education to dispel misconceptions and mistrust

• Complex research and execution necessary, feels more like an obligation than a primary goal

Criticism, issues, and concernsLack of massive funding and interest (Philippines) impedes progress

• Low public spending on research and development

• R&D allocated to 3% of Environmental Protection 2018 budget

• Private companies will invest if methods are profitable; however, maintaining the environment is seen as more of the government's job

• DOST's budget (correlated to public R&D spending) is 0.12% of all government expenditures

BioremediationFigure 3 Health, safety and environment workers contracted by British Petroleum clean up oil on a beach in Louisiana following the Deepwater Horizon oil spill (US Coast Guard, 2010)

IntroductionBioremediation is a treatment that uses naturally occurring organisms to break down hazardous substances into less toxic or non-toxic substances.

Figure 4 Algae flourishing in a pond

Introduction

Since conventional methods for cleanup (such as incineration or dumpsite burial) are not necessarily environmentally-friendly and may pose significant hazards in the future, bioremediation shows great promise in terms of cost as well as in mitigating risk.

Figure 5 Orange peels revitalizing barren land in Costa Rica

Classifications

Mycoremediation uses fungi

Phytoremediation uses plants

Microbial remediation uses microorganisms

Bio

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In situ

Natural attenuation

Enhanced

Bioslurping

Bioventing

Biosparging

Phytoremediation

Ex situ

Biopile

Windrow

Bioreactor

Land farming

In situ bioremediation

• Involves remediation of pollutants using inherent metabolic activity of the microorganisms

• It is more cost-effective and noninvasive to leave contaminated soil and water in place while bioremediation happens

• Microorganisms or the site of which the pollutants are to be removed are not manipulated and everything is left in its place

• Biostimulation is the process of accelerating bioremediation by supplying key nutrients.

In situ bioremediation

• Natural attenuation and enhanced techniques

• Bioventing

• Uses indigenous microorganisms to degrade the pollutants in soil

• Adding some air to soils to support bioremediation

• A sufficient supply of oxygen ensures an optimal growth rate, and an optimal growth rate ensures rapid breakdown of environmental contaminants.

• Wells are made at the point of contamination or pollution above water level through which air/nutrients are injected

• Has been proven to be very effective in remediating petroleum contaminated soil

In situ bioremediation

• Bioslurping

• Technique combines vacuum-enhanced pumping, soil vapor extraction and bioventing to achieve soil and groundwater remediation by indirect provision of oxygen and stimulation of contaminant biodegradation

• Designed for free products recovery such as light non-aqueous phase liquids (LNAPLs), thus remediating capillary, unsaturated and saturated zones. It can also be used to remediate soils contaminated with volatile and semi-volatile organic compounds.

• Uses a slurp that extends into the free product layer, which draws up liquids (free products and soil gas) from this layer in a manner similar to that of how a straw draws liquid from any vessel

• Not suitable for remediating soil with low permeability

• Saves cost due to less amount of groundwater resulting from the operation thus minimizes storage, treatment and disposal costs

In situ bioremediation

• Biosparging

• Air is injected at the saturated zone

• Oxygen and nutrients (if needed) are injected into saturated zone to increase the biological activity of indigenous microorganisms

• Widely used in treating aquifers contaminated with petroleum products, especially diesel and kerosene

• Can be used to reduce the petroleum products that are dissolved in ground water or absorbed to the soil below water level

In situ bioremediation

• Phytoremediation

• Choosing the plant

• Root system

• Above ground biomass

• Toxicity of pollutant to plant

• Plant survival

• Adaptability to prevailing environmental conditions

• Plant growth rate

• Time required to achieve desired level of cleanliness

• Resistant to diseases and pests

Ex situ bioremediation

• When the contaminant is especially toxic or the potential for exposure is too great, the contaminated soil or water must be removed from the environment and treated off-site, still using bioremediation, just changing where it is happening

• Excavating pollutants from polluted sites and subsequently transporting them to another site for treatment

• Biopile

• Above-ground piling of excavated polluted soil, followed by nutrient amendment, and sometimes aeration to enhance bioremediation by basically increasing microbial activities

• Help limit volatilization of low molecular weight (LMW) pollutants; it can also be used effectively to remediate polluted extreme environments such as the very cold regions

Ex situ bioremediation

• Windrows

• Periodic turning of polluted soil, together with addition of water bring about increase in aeration, uniform distribution of pollutants, nutrients and microbial degradative activities, thus speeding up the rate of bioremediation

• Windrow treatment when compared to biopile treatment, showed higher rate of hydrocarbon removal; however, the higher efficiency of the windrow towards hydrocarbon removal was as a result of the soil type, which was reported to be more friable.

• May not be the best option to adopt in remediating soil polluted with toxic volatiles. The use of windrow treatment has been implicated in CH4 (a greenhouse gas) release due to development of anaerobic zone within piled polluted soil, which usually occurs following reduced aeration.

Ex situ bioremediation

• Bioreactor

• Vessel in which raw materials are converted to specific products following series of biological reactions

• Can be used to treat liquid effluents or contaminated solid waste

• Degradation is very rapid and efficient; however, the cost of a bioreactor is high

• Different operating modes of bioreactor

• Batch, fed-batch, sequencing batch, continuous and multistage

Ex situ bioremediation• Land farming

• One of the simplest bioremediation techniques owing to its low cost and less equipment requirement for operation

• Above ground remediation technology for hydrocarbon (petroleum) contaminated soils through biodegradation

• Solid phase treatment system for contaminated soils

• Contaminated soil is excavated, mixed with microorganisms and nutrients, and spread out on the ground surface or liner. soil is regularly turned for mixing and aeration

• Efficiency of biodegradation can be increased by optimizing temperature and nutrients in the contaminated soil. Addition of co-substrates and anaerobic pre-treatment of the soil also enhances degradation process.

• Successfully used for bioremediation of benzene, toluene, and xylene (BTX pollutants)

• Permeable reactive barrier

Criticism, issues, and concerns

• Inadequate understanding of the microbial process

• Low success rate

• Slow process (takes months to years)

• Unavailability of contaminants

• Too low concentration of the contaminants leads to the sequestering of the contaminants from the microorganisms

• Toxicity of contaminants

• High concentration of contaminants can be toxic to microbes, preventing or slowing down metabolic reaction of the microbes.

Criticism, issues, and concerns

• Microbial preference

• Bioremediation efforts are wasted when targeted contaminants are accompanied by other substantial quantities preferred by the microbes (diauxy)

• Partial degradation of contaminants, producing hazardous byproducts

• May create intermediates that is more toxic than the parent contaminant

• Inability to remove contaminants to very low concentrations

Criticism, issues, and concerns

• Aquifer clogging from excessive biomass growth

• Interferes with effective circulation of nutrient solution

• Ways to promote contaminant transport

1. High pressure fracturing of the subsurface matrix

2. Solubilization of the contaminants by injecting heat via steam, hot air, or hot water

3. Addition of surfactants

• Hard to monitor both microorganisms and contaminants on the subsurface

References

1. Referees, Guide To. "Environmental biotechnology - Latest research and news | Nature." Nature.com. 7 Nov. 2014. Web. 16 Nov. 2017. https://www.nature.com/subjects/environmental-biotechnology

2. Rittmann, Bruce E., and Perry L. McCarty. "Environmental biotechnology: principles and applications." Tata McGraw-Hill Education, 2012.

3. Lecia Bushak. "A Brief History Of GMOs." Medical Daily. 22 Jul. 2015. Web. 16 Nov. 2017. http://www.medicaldaily.com/brief-history-genetically-modified-organisms-prehistoric-breeding-modern-344076

4. United States Environmental Protection Agency. "A Citizen's Guide to Bioremediation." Clu-in.org Web. 16 Nov. 2017. https://clu-in.org/download/Citizens/a_citizens_guide_to_bioremediation.pdf

References

5. N.a. "Environmental-Biotechnology." Biotechonweb.com. 12 May 2017. Web. 16 Nov. 2017. http://www.biotechonweb.com/environmental-biotechnology.html

6. N.a. "3.10 In Situ Physical/Chemical Treatment for Ground Water and Leachate." Frtr.gov. 9 Jan. 2016. Web. 16 Nov. 2017. https://frtr.gov/matrix2/section3/3_10.html

7. N.a. "Ex situ treatment technologies." Eugris.info. n.d. Web. 16 Nov. 2017. http://www.eugris.info/FurtherDescription.asp?Ca=2&Cy=0&T=Ex+situ+treatment+technologies&e=25

8. Belkin, Shimshon, et al. "Remote detection of buried landmines using a bacterial sensor." Nature Biotechnology 35.4 (2017): 308-310.

References

9. Rittmann, Bruce E., and Perry L. McCarty. "Environmental biotechnology: principles and applications." Tata McGraw-Hill Education, 2012.

10. National Research Council. In situ bioremediation: When does it work?. National Academies Press, 1993.