ABSTRACT
I. INTRODUCTION Synthetic chemicals from petroleum origins are now coming at a turning point for their hazardous problems to living organisms. Concerns about environmental protection and the safety for health have introduced an interest in developing biomaterials such as naturally occurring surfactants (biosurfactants), biodyes, biopolymers, and fine chemicals [1 ,2]. It is historically significant that many naturally occurring surfactants of animal and plant origins have contributed to daily lives. Biomembranes present a prosperous museum of natural amphiphiles [3]. Some part of them have been industrially produced as chemicals. However, their supplying volume sometimes has been unstable depending on the unusual climate and natural calamity. It has been reported in the R & D studies of single-cell proteins since 1969 that some part ofhydrocarbon-assimilating bacteria excrete surface-active substances. These microbial surfactants are classified as biosurfactants-microbial biosurfactants, bioemulsifiers, and so on [4,5]. The merits of microbial production processes include (1) the ease of cultivation due to the establishment of fermentation industry, (2) the higher growth rate of microbes, (3) the efficient production rate of biosurfactants, and (4) the expectation of finding new functional materials. The items in (3) and (4) are now being developed [6]. Characterization ofbiosurfactants is described in the first edition of this book [7].
