Bioleaching: Mineral-Dissolving Bacteria Help us Obtain Valuable Metals but Produce AMD | GEO GIRL

This video covers biomining techniques, specifically bioleaching and bio-oxidation. But before we discuss these techniques, we go through the underlying mechanisms behind microbial metal oxidation/leaching by using Fe-sulfide oxidation as a prime example. Metal sulfide deposits contain valuable metals that we can collect through bioleaching, but only specific microbes are able to oxidize such metals and some of these microbes do a better (more efficient) job than others, so we study these microbial processes to pick the best species for biomining. Once we chose the most efficient microbial species for dissolving the target metal in a sulfide deposit, and we identify the metabolic needs of the species so we can maintain optimal bacterial growth, we can move forward with the bioleaching process by using either dump bioleaching or heap bioleaching (both discussed in the video). However, when using iron sulfide dissolving microbes in bioleaching, the runoff that is not collected often creates an environmental hazard known as acid mine drainage because the microbes are acidophiles (they grow best in acidic conditions) and the process they induce to dissolve the metal sulfide only increases the acidity, creating a highly corrosive and dangerous effluent. I talk more about the environmental concerns of acid mine drainage (AMD) in the video. Lastly, we briefly touch on everyone's favorite metal, gold (Au), and the biooxidation process necessary for obtaining such a refractory metal, and how biooxidation differs from bioleaching. Hope you enjoy! :) References: Geomicrobiology: https://amzn.to/2WAloTR Biology of Microorganisms: https://amzn.to/3kQqIuD GEO GIRL Website: https://www.geogirlscience.com/ (visit my website to see all my courses, shop merch, learn more about me, and donate to support the channel if you'd like!) 0:00 Fe oxidation (rusting) 2:00 steps of pyrite oxidation 5:25 how acidity affects pyrite dissolution 6:58 role of microbes in mineral dissolution 8:33 how microbes mediate pyrite dissolution 10:15 other microbes could do the opposite 11:24 direct vs indirect microbial role 12:17 role of EPS in microbial weathering 13:25 different microbes oxidize different sulfide minerals 14:02 acid mine drainage- environmental impact 15:28 what is bioleaching? 17:23 dump vs heap bioleaching 18:24 how we grow bacteria for bioleaching 20:42 we also use fungi for bioleaching 21:57 can we biomine gold? 23:18 upcoming videos & references! Hey there, Earth enthusiast! Check my favorite Earth-friendly products: Bamboo toilet paper: https://shrsl.com/3cvku Bamboo paper towels: https://shrsl.com/3cvkw Compostable tableware: https://shrsl.com/3cvkz Compostable trash bags: https://shrsl.com/3cvl0 Bamboo cutlery + straw! : https://shrsl.com/3cwfl Eco-Friendly Tote (great for grocery shopping!): https://shrsl.com/3cwfp Reusable straws + cleaning brushes (my fav!): https://shrsl.com/3cwft Eco-friendly laundry detergent: https://shrsl.com/3cwgo Directly offset your carbon footprint with Wren: https://shrsl.com/3d0t2 (Just click link, press get started, take the free C footprint quiz, then choose how much you want to reduce your footprint by donating to the C sequestration projects they're funding!) Non-textbook books I recommend: Oxygen by D. Canfield: https://amzn.to/3gffbCL Brief history of Earth by A. Knoll: https://amzn.to/3w3hC1I Life on young planet by A. Knoll: https://amzn.to/2RBMpny Some assembly required by N. Shubin: https://amzn.to/3w1Ezm2 Your inner fish by N. Shubin: https://amzn.to/3cpw3Wb Oxygen by N. Lane: https://amzn.to/3z4FgwZ Alien Oceans by K. Hand: https://amzn.to/3clMx1l Life's Engines: https://amzn.to/3w1Nhke Tools I use as a geologist/teacher/student: Geology field notebook: https://amzn.to/3lb6dJf Geology rock hammer: https://amzn.to/3DZw8MA Geological compass: https://amzn.to/3hfbdLu Geological hand lens: https://amzn.to/3jXysM5 Camera: https://amzn.to/3l6fGRT Carbon-neutral pencil bag: https://shrsl.com/3cvjv Carbon-neutral backpack: https://shrsl.com/3cvkc Disclaimer: Links included in this description might be affiliate links. If you purchase a product or service with the links that I provide I may receive a small commission, but there is no additional charge to you! Thank you for supporting my channel so I can continue to provide you with free content each week! And as always, let me know your topic suggestions in the comments down below!