Characteristics of resting state colonies of the Alga Botryocccus braunii obtained from a bloom of the organism

Abstract

Resting state colonies from an extensive bloom of the alga Botryococcus braunii were predominantly green in appearance and had an extremely high proportion of matrix to cells. The surface of the matrix was characterized by the presence of cups, i.e. small depressions, each containing a unit cell of the colony. The cups were composed of concentric membranes (6-8) extending down through the matrix of the colony and separated by translucent material. Below this region were further series of membranes of larger parent cups also containing translucent material. Small sac-like vesicles were present throughout the cups, both along and between the membranes. Pores and sinuses were observed along the medial sections of the colony.

When maintained in suspension the unit cells detached from the cups, resulting in an apparent colour change to the colonies. The hydrocarbon composition of the detached cells closely resembled that of the colonies, although the major hydrocarbon store was located in the matrix. Colonies produced considerable amounts of extracellular mucilage and were characterized by a distinctive odour due to the presence of short-chain fatty acids.