To Compost or Not to Compost? Student Spotlight on Kyle Jacobs
Kyle Jacobs, a recent Virginia Tech graduate with a Master’s in Biological Systems Engineering in the College of Engineering, found himself spending a large portion of his graduate life using a shovel. In fact, he and his colleagues spent a week–working from seven in the morning until dark–digging 27 three-by-three meter plots in the Urban Horticulture Center off of Prices Fork Road.
All of that digging and monitoring, though, is for a good reason. Jacobs and his research team were trying to determine if composting is an effective tool to prevent the transfer of antibiotic resistant bacteria and genes to crops grown with manure.
Jacobs’ two advisors in the college of engineering, W. Cully Hession, Professor of Biological Systems Engineering, and Leigh-Anne Krometis, Assistant Professor of Biological Systems Engineering, are Co-Principal Investigators and members of the core Project Team dedicated to reducing antibiotic resistance. The Principal Investigator of the project is Amy Pruden, a Professor of Civil and Environmental Engineering.
Farmers use antibiotics as a precaution to ensure that their cattle remain healthy and in order to prevent the spread of disease. Antibiotic resistance has the possibility of being transferred to people from the soil that is used to grow crops, even though the antibiotics given to cows and humans are different.
Composting is one possible solution to this problem, because the composting process reaches high temperatures, and may therefore rid the soil of most bacteria. Bacteria that live in the gut of mammals are at body temperature (37 degrees Celsius or 98.6 degrees Fahrenheit), and composting them will raise the temperature to 55 degrees Celsius (131 degrees Fahrenheit). The idea is that this increase of roughly 40 degrees would effectively kill microorganisms that pose a disease risk.
Jacobs and his advisors have noticed, however, that while composting kills some bacteria, it seems to “stress out the [remaining] bacteria” and may actually increase surviving bacteria’s resistance to antibiotics.
In order to test the effectiveness of composting, Jacobs fed antibiotics to cows in known amounts. Then the team collected the cows’ manure and used it in the soil of the land plots. Each plot differed: some were given compost with or without antibiotics, some had raw manure with or without antibiotics, and others served as controls where nothing had been added.
Jacobs’ job was to test the runoff from each plot. “I had to rely on the weather,” Jacobs said, “which is really hard to predict here [in Blacksburg].”
If there was a 60 percent chance or higher of rain, Jacobs would prepare his equipment so he could quickly collect the first flush of rainwater once the storm started -- even in the early hours of the morning.
Jacobs built four 1-gallon buckets into each land plot, which were designed to collect only the first flush. His ultimate goal is to count the antibiotic resistant genes in the samples of that runoff.
After spending the first half of his research out in the field, building plots during shovel parties and collecting data in the rain, Jacobs is eager to see what will come of the testing and how it will further support the discoveries found in the soil. He will, however, miss the shovel parties.
“I will never underestimate agricultural work and studies ever again, it’s a lot of work,” Jacobs reminisced.
Salem, Virginia, which is about 30 minutes away from here. I was actually born in Blacksburg.
Recently defended M.S. at Virginia Tech. Area of focus: Ecological engineering, antibiotic resistance associated with agriculture and storm water management.
W. Cully Hession, Professor of Biological Systems Engineering in the College of Engineering
Leigh-Anne Krometis, Assistant Professor of Biological Systems Engineering in the College of Engineering
What are you planning on doing with your Masters?
I am hoping to get into an Environmental Consulting Firm for Environmental Engineering.
What attracted you to your particular field of science?
I have always been environmentally conscious. However, Virginia Tech doesn’t have a specific environmental engineering field, there are really only two choices: civil engineering, with an environmental engineering subset, and biological systems engineering (which used to be called agricultural engineering). What biological systems tries to do is minimize the destruction to the environment and make it help us as people.
Are you interested in any other fields of science?
Oh, of course. I have a telescope, I look at space all the time.
I’ve even taken some medical courses because I wanted to better understand my own research. My research focuses on microbiology and engineering, so it’s interesting to combine the two into one.
What is the most important quality for a scientist to have?
I think it’s good to be multidimensional [work in interdisciplinary fields].
Do you have a favorite piece of lab equipment?
I wouldn’t call this lab equipment, per se, but my advisor [Hession] has this big helicopter that he flies around. That’s pretty fun, and it’s usually in the lab!
Favorite hobbies outside of school and research?
I play soccer. I cook a lot, too. I really enjoy cooking for people. I’ll call my friends up and say “Hey come over, I’ll cook for you.”
Article written by Kayleigh Green while participating in ENGL 4824: Science Writing in Spring 2017 as part of a collaboration between Fralin and the Department of English at Virginia Tech.