Immobilization of cultured Catharanthus roseus cells using a fibreglass substratum

Abstract

Cultured C a t h a r a n t h u s roseus cells were immobilized using geometrically identical needled fibreglass mats prepared with a range of surface coatings. The phenyl (PS), polyglycol (PG), aldehyde (CHO), alkyl (CTMS), and silanol (AW) coatings, along with the untreated glass (HC) surface, produced surfaces with a range of surface tensions. The immobilization efficiency of the substratum, measured as the percentage of cells immobilized, increased with increasing substratum surface tension in the order PS < PG < CHO < CTMS < AW < HC. The dependence of immobilization efficiency on substratum surface tension can be described using a thermodynamic model of adhesion that considers the extent of plant cell adhesion to be a function of the surface tensions of the substratum, the suspending liquid, and the plant cells. In addition, this dependence also demonstrates the fundamental role of adhesion in the immobilization process involving a glass fibre matrix. However, cell entrapment processes are also implicated. The untreated glass fibre substratum (HC), which demonstrated the greatest immobilization efficiency, was used for further characterization of the immobilization strategy. Maximum inoculum biomass was determined to be approximately 1.9 g cells (fresh weight)/g substratum (dry weight) to achieve greater than 90% immobilization efficiency. The growth rate of immobilized cultures was slower than suspension cultures, probably due to mass transfer limitations. Production of the indole alkaloids, tryptamine, catharanthine, and ajmalicine, was also suppressed relative to suspension-cultured cells. These results are considered in relation to other immobilization strategies and their apparent effects on cellular processes.

Biomass production, carbon and oxygen consumption by Rhizopus arrhizus grown in submerged cultures on thin liquid films or immobilized on fibrous and particulate materials

“…Since the porosities and densities of all these materials were very similar, fungal growth and adhesion to the matrix seemed to have been affected more by the fungal affinity towards the support in relation to the surface tension of the carriers, their free chemical groupings and added adjuvants, than by their physical characteristics alone, as shown previously by Facchini and DiCosmo (1990). The increase in biomass yield observed that was associated with higher sucrose consumption might have been the result of higher carbon assimilation because of better cell oxygenation.…”

The scale-up of plant cell culture: Engineering considerations

“…Few immobilized systems have been used in the production step because secondary meta- [108] C. roseus [69,109] M. pruriens [110] Reticulate polyurethane matrix C. frutescens [111] D. deltoidea [112] Ceramic hollow fiber C. roseus [48] Polyester fiber matrix C. roseus [113] N. tabacum Soybean Surface-coated fiberglass C. roseus [114] bolites are generally intracellular in nature, however, they have been used with success in biotransformations. Alfermann et al were able to convert fl-methyldigitoxin to digoxin using D. lanata immobilized in Ca-alginate beads [115].…”

Bioreactors for surface-immobilized cells

“…In the first stage, cells are spontaneously attracted to the support surface due to van der Waal's forces, aided by entrapment of ceils in pores or other irregularities on the surface of the support (Facchini & DiCosmo 1990, Facchini et al 1989). Subsequently, plant cells appear to secret a mucilaginous substance of some sort, thereby firmly cementing themselves to the support surface (Archambault et al 1989;Rhodes et al 1985;Robins et al 1986).…”

“…The development of Facchini-DiCosmo surface immobilization technology has been described in a succession of published articles (DiCosmo et al 1988;Facchini et al 1988a, b;Facchini et al 1989;Facchini & DiCosmo 1990, 1991a. Considerable insight into the theoretical and thermodynamic aspects of plant cell immobilization on polymer surfaces has also been gained.…”

“…Maximum production Linear phase (mg/g dry weight/day) (mg/g dry weight) phenyl, polyglycol, aldehyde, alkyl, or silanol coating (Facchini & DiCosmo 1990, 1991b. Coating resulted in surfaces with a range of surface hydrophobicities, all with lower surface tensions than the uncoated fibreglass.…”