Maintaining nitrogen-limited balanced-growth states in a cyclo-turbidostat

Abstract

This dissertation presents two separate studies on the green microalga Picochlorum oklahomense. The first study investigates the minimum nitrogen cell quota required to support maximum growth rate and the effects of nitrogen limitation on cycloturbidostat cultures under steady-state, balanced growth conditions. This study introduces the concept of the threshold of nitrogen cell quota necessary to support maximum growth rate denoted as Q⌄N, T. The second study provides empirical evidence of multiple fission in Picochlorum oklahomense grown in light-saturated turbidostats and in semi-continuous cultures. We present evidence that Picochlorum oklahomense is an autosporic species and produces 2 to 4 daughter cells per mother cell via a multiple fission pathway. Additionally, the paper discusses the utility of turbidostats in experimental phycology and provides an outline of cycloturbidostat fundamentals. Lastly, this dissertation uses unpublished data from preliminary trials to describe potential issues encountered when utilizing cycloturbidostats in the laboratory, particularly in nutrient-limitation studies. The study highlights the importance of microalgae in understanding algal biology and building valuable year-round supply chains.