Date of Completion


Degree Type

Honors Thesis - Campus Access


Biology (BIOL)

First Advisor

Dr. Nancy Fujishige


In the wake of an ever-warming planet, awareness regarding the negative environmental and health effects of traditional fertilizers on crop farms has spiked. Consequently, alternative measures to promote crop growth while avoiding dangerous environmental and health costs continue to be sought. The symbiotic relationship between plants and microbes serves as a promising alternative for crop farms. Bacillus simplex 237, isolated from the rhizosphere of the Negev Desert in Israel, has been documented to display plant growth promoting properties. While the formation of microbial biofilms plays a role in the mutualism between plants and bacteria, much has not been studied regarding the ability of B. simplex 237 to form biofilms and to promote plant growth. Time-coursed biofilm assays along with microscopy were performed in different growth media—Brain Heart Infusion (BHI), Lysogeny Broth (LB), Tryptone Yeast (TY), and Hoagland’s + 1% sucrose (HS)—over 24hr, 48hr, and 72hr intervals to measure the environmental conditions that promote biofilm formation and to characterize the formation. Antifungal assays and microscopy were also performed in this study to observe and describe the plant growth promoting properties of this bacterial strain. The quantification of the biofilm assay suggested that nutrients availability induces the attachment of the bacteria leading the cells to form biofilms.