Quantitative Analysis of Bromoform Production in Seaweed via GC-MS
Evan Forrest, Juan Armas
Department of Chemistry & Biochemistry
Faculty Supervisor: Raymond Esquerra
Seaweed has been touted as a natural supplement to reduce greenhouse gas emissions from ruminant livestock animals. This is due to a secondary metabolite that seaweed produces called bromoform which is known to inhibit methyl-coenzyme M reductase, the final step of methane formation in the rumen. By including bromoform as a supplement in ruminant livestock methane emissions will be lowered by 50% when included in cattle feed. Moving forward now that California law dictates livestock emission must be below 40% below 2013 levels by 2030, sequestering methane emissions becomes a more important mission. As well as in the fight for climate change using seaweed to sequester methane is highly valued because methane is 25x stronger than carbon dioxide at trapping heat and almost ¼ of the world's methane is produced by ruminant livestock. While all seaweed produces bromoform and seems like a promising solution to reduce greenhouse gases differences in their localization of the vanadium dependent bromoperoxidase and the storage of bromoform between green, brown, and red seaweeds yield to vastly different bromoform concentrations. To go beyond the known literature, we will collect a larger data set of different seaweed species across the San Francisco Bay Area and quantify their bromoform concentration. To understand the variables that cause difference in bromoform production we will culture seaweed alerting light condition, temperature, and add substrates that lead to bromoform production. An alternative solution to seaweed is to make bromoform bio synthetically in Escherichia coli (E. coli). We will do this by using a functionally equivalent vanadium haloperoxidase be fused to an oxidase enzyme that generates hydrogen peroxide. To analyze these samples, we are using the Agilent 7000E Gas Chromatography Mass Spectrometry (GC/MS) instrument to create a library of bromoform concentrations.