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Bioremediation & Biorecovery- How biology can remove metals from the environment! | GEO GIRL - YouTube
Channel: GEO GIRL
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hi guys today we're going to be talking about聽
bioremediation and biorecovery and specifically聽聽
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the underpinning mechanisms behind bioremediation聽
and biorecovery so let's get started聽聽
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so we talked in the previous video over cell walls聽
and bioabsorption i'll link it up here if you want聽聽
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to check it out about microbial surface reactivity聽
and this video about bioremediation and recovery聽聽
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relates to that video in that the fundamental聽
mechanisms behind bioabsorption are what allow聽聽
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us to do something called bioremediation so聽
what is bioremediation in the first place well聽聽
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we release metal pollutants and contaminants聽
into the environment and one way to remove聽聽
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these contaminants is by employing the metal聽
binding properties of microbial biomass these聽聽
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are some of the properties that we talked聽
about in that previous video and we'll talk聽聽
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more about here today but what do i mean by聽
biomass exactly well it turns out that both聽聽
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living and dead microorganisms can efficiently聽
bind metals and there are several different聽聽
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ways in which microbes can bind these metals these聽
different ways or mechanisms are sometimes called聽聽
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slightly different names but in general the four聽
main categories of ways that microbes bind metals聽聽
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include bioabsorption bioaccumulation聽
biotransformation and biomineralization聽聽
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in the case of biotransformation we talked more聽
about the ways that microbes bio transform metals聽聽
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and just other chemicals in general in the聽
metabolic diversity and redox videos and聽聽
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we'll also talk more about biotransformation聽
as well as biomineralization in the upcoming聽聽
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biomineralization videos there are going to聽
be a few or several bio mineralization videos聽聽
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because as i'm making this i'm also working聽
on those videos as well the power points for聽聽
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those and there's just a lot to talk about but聽
it's really really cool and interesting what聽聽
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biology can do to mineralize well minerals聽
and we'll talk about that in those videos聽聽
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as well as more about biotransformation but in聽
this video we're going to be talking more about聽聽
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bioabsorption and bioaccumulation first we'll聽
talk about bioabsorption bioabsorption is the聽聽
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passive adsorption of metals onto microbial聽
surfaces what does this mean well adsorption聽聽
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rather than absorption is the absorption of聽
metals onto microbial surfaces rather than聽聽
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into microbes themselves whereas absorption聽
with a b is absorption into and that applies to聽聽
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absorption or absorption of anything it's聽
not just with microbes so in the case of聽聽
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bioabsorption we're talking about the passive聽
adsorption of metals onto microbial surfaces聽聽
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and the pros of using this type of method聽
this bioabsorption method for bioremediation聽聽
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include that is inexpensive the biomass can be聽
easily regenerated it is non-hazardous waste and聽聽
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you can choose the selectivity of your bacteria or聽
microbes that you're utilizing for specific metals聽聽
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by this i mean that there are different bacteria聽
that we know bind with specific metals and you can聽聽
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choose which one you want to bind your certain聽
contaminant that you know is in that area that聽聽
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you want to remediate or remove and after using聽
biomass for bioabsorption remediation the metal聽聽
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laden bioabsorbent that you use can be dealt with聽
by incineration so you can incinerate the biomass聽聽
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and then dispose of the ash at landfills or you聽
can reuse it like we talked about in previous聽聽
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slide you can regenerate the biomass after the聽
absorbing has happened by doing what's called聽聽
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desorbing so you can desorb the metals from the聽
biomass and then regenerate that bioabsorbent for聽聽
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another round of bioremediation but moving聽
on from bioabsorption to bioaccumulation聽聽
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what are the differences between bioabsorption聽
and accumulation and is bioaccumulation better聽聽
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or worse to use as a bioremediation technique well聽
bioaccumulation refers to the active absorption of聽聽
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metals or contaminants into the cell rather than聽
onto the cell and it's an active process rather聽聽
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than a passive process so what does this mean聽
it means that metals or contaminants whatever聽聽
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you're remediating from that environment whatever聽
contaminant you are targeting the bacteria or聽聽
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microbe is actively taking up that compound into聽
its cell by a enzymatic transport system which is聽聽
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often by accident so typically they have transport聽
systems for nutrients they need to take into their聽聽
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cell and sometimes they accidentally take up聽
something that is structurally analogous to the聽聽
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nutrient they're actually targeting and they take聽
up something toxic that benefits our purposes of聽聽
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using bioaccumulation because that is what we're聽
targeting we're targeting these cells to take up聽聽
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this toxic metal that's in the environment and聽
so they accidentally take up this toxic metal or聽聽
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material into their cell through this transporter聽
that's meant for something else that just looks聽聽
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similar and once it's in their cell they can't聽
necessarily use it so it kind of accumulates there聽聽
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and that's why it's called bioaccumulation聽
and such bioaccumulation can work its way up聽聽
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the food chain to start accumulating these聽
toxic metals in larger macro multicellular聽聽
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organisms just by them eating the smaller things聽
that first ate or took up that toxic compound聽聽
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so this accumulation pattern can not only聽
happen in bacteria and microbial cells but also聽聽
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in larger organisms as the accumulation works its聽
way up the food chain and continues to accumulate聽聽
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somebody count how many times i said accumulate聽
in the past five minutes anyway i do want to point聽聽
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out that there are plenty of microbes that target聽
and take up metals even ones that are toxic to us聽聽
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on purpose for their metabolic needs however this聽
doesn't necessarily fall into bio accumulation聽聽
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category it falls under biotransformation聽
instead of taking up the metal by accident into聽聽
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a transport system that wasn't meant for it and聽
then accumulating within the cell they actually聽聽
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take up the metal or whatever compound it is for聽
their metabolic activity and they take it in their聽聽
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cell and they transform it into something else聽
by their metabolism and chemical transformation聽聽
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and then they release whatever their byproduct聽
is after they transform it it's kind of like how聽聽
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we take up oxygen and sugars and we respire and聽
convert it all into carbon dioxide and that's聽聽
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what our byproduct is anyway the cons of using聽
bioaccumulation it to bioremediate environments聽聽
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is that living microbial populations must be kept聽
alive obviously and this requires keeping the聽聽
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environment at a specific ph specific temperature聽
having sufficient nutrient supply and more just to聽聽
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keep those microbes alive and they also have to be聽
kept uncontaminated by other species and microbial聽聽
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communities which could be really hard when you're聽
trying to remediate something in the natural聽聽
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environment those controlled conditions are much聽
easier to meet in isolated environments that you聽聽
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create in the lab so actually employing this聽
method for remediating environments would be聽聽
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really difficult just to keep those parameters met聽
the other con listed here is that intracellular聽聽
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metals are really hard to recover so what does聽
this mean basically we know that bioaccumulation聽聽
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takes the metal into its cell rather than聽
just absorbing it onto the surface of itself聽聽
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because of this it's really hard to get that聽
metal out when it's time to try and reuse those聽聽
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bioaccumulators for another round of remediation聽
instead they have to be destroyed and they cannot聽聽
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be reused like bioabsorbent bacteria can be for聽
remediation purposes instead of just being able聽聽
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to desorb the metal you have to literally destroy聽
the cell in order to recover the metal in the聽聽
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case of bioaccumulation the last thing i want to聽
discuss regarding bioremediation before we move to聽聽
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biorecovery is that microbes are not the only聽
living things that can bioabsorb or accumulate聽聽
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metals and be employed to bioremediate聽
environments instead there are also macro聽聽
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organisms like plants for example that can also聽
be used metal uptake by plants is study for聽聽
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two main reasons not just remediation but also to聽
understand the possibility of crop contamination聽聽
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and subsequent toxicity of crops due to uptake of聽
contaminants from the groundwater however in the聽聽
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case of bioremediation bioremediation using plants聽
is called phytoremediation so last i want to talk聽聽
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about by recovery first why is the recovery聽
of metals important we just talked about how聽聽
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their contaminants we want to take them out of the聽
environment and we don't want to see them they're聽聽
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icky no no fun nobody likes metals well that's not聽
the case for all metals some metals can be pretty聽聽
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valuable to us for example what are you watching聽
this video on i bet it's made of metal what we聽聽
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don't grow we have to mine and in some cases聽
economically valuable metals are in solutions and聽聽
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cannot be traditionally mined and in many聽
instances they are present at such low聽聽
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concentrations that we have to employ biology聽
in order to recover the economically valuable聽聽
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metals or materials that are in those solutions聽
recovering metals using biology from solutions聽聽
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where their concentrations are too low to do聽
abiotically is called biorecovery the actual聽聽
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processes associated with biorecovery are pretty聽
much the same as those used for bioremediation聽聽
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however again it's more favorable to use by聽
absorbing than it is to use bioaccumulating聽聽
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because you want to easily obtain those metals聽
after you cover them and you also want to be able聽聽
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to reuse the biomass if possible so after you use聽
bioabsorbing to recover your metals desorption can聽聽
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be achieved by using specific eluents or desorbing聽
agents and or adjusting the ph or employing聽聽
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organic ligands that bind the specific metal聽
that you are after so again bioaccumulation聽聽
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and assimilation are not super favorable but can聽
also be used in the case of by remediation and聽聽
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recovery whereas bioabsorption is the favorable聽
method of bioremediation and recovery because聽聽
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you can easily desorb the metal contaminants聽
or precious metals that you want after you聽聽
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absorb them onto your biomass and therefore聽
you can reuse the biomass after desorption聽聽
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and biotransformation as well as bioleaching聽
precipitation biosynthesis biodegradation聽聽
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and again bioabsorption and bioaccumulation in聽
the stimulation will all be talked about in the聽聽
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upcoming biomineralization videos so i hope to see聽
you guys all there when we go over the difference聽聽
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between induced and controlled biomineralization聽
in the part one biomineralization video and then聽聽
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the examples of induced biomineralization of iron聽
hydroxide magnetite manganese oxides clays and聽聽
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amorphous silica in the part two biomineralization聽
video and then more examples will be to come聽聽
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in the part three four and five of these bio聽
mineralization videos i know that seems like a lot聽聽
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but i swear i was going through it and i was like聽
this is way too much to put into one video so you聽聽
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guys are gonna get a five part bio mineralization聽
mini series i guess for the geo bio videos coming聽聽
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up and i hope you guys come back for those and i聽
see you there and lastly the reference i'm using聽聽
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again is geomicrobiology or this video um by聽
kurt konhauser as always i love this book super聽聽
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informative and hats off to kurt konhauser for聽
writing a five part biometrialization chapter聽聽
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or at least in my brain it's five part he聽
does it all in one chapter i don't know how聽聽
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anyhow that's it for this video and聽
any other of my minor references and聽聽
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image sources are always also in my description as聽
well as that book is linked in my description so聽聽
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go check that out if you're interested and with聽
that i'll see you guys next time bye for certain聽聽
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spa certain i was going to say specific and then聽
i said certain instead okay it's been a long day
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