Thermostable lipolytic enzymes production in batch and continuous cultures of Thermus thermophilus HB27

Abstract

Several studies in laboratory-scale bioreactors are undertaken in order to verify the beneficial effect of thermal spring water in the culture medium of Thermus thermophilus HB27. Two bioreactor configurations, stirred tank and airlift, are investigated to determine the most suitable one to develop a continuous process. Water mineral composition affects the lipolytic enzyme secretion and growth of T. thermophilus HB27 in both bioreactor configurations. Furthermore, the lipolytic activity is strongly enhanced when stirred tank bioreactor is used. Moreover, operation in a stirred tank at an agitation rate of 650 rpm leads to the highest total lipolytic activity (intra- and extracellular enzyme) around 280 U/L after 32 h. Continuous cultures operating in the optimised conditions determined in batch cultures are carried out. It is noticeable that the stirred tank bioreactor was able to operate in a continuous flow mode without operational problems. In addition, the lipolytic activity obtained is about 2-fold higher than that attained in batch cultures.

Efficient biosynthesis of a chitinase from Halobacterium salinarum expressed in Escherichia coli

“…The search for more efficient bioprocesses at an industrial scale has prompted the investigation of a number of small‐scale bioreactor systems, which tended to focus on stirred tank or airlift designs because of their geometrical similarity with the large‐scale bioreactors most likely to be used for industrial manufacture . Besides, these configurations allow evaluating the importance of different decisive engineering variables such as agitation and aeration on the production of chitinolytic enzymes.…”

Continuous cultivation of a thermophilic bacteriumAeribacillus pallidus418 for production of an exopolysaccharide applicable in cosmetic creams

“…; Teodoro and Martins ; Domínguez et al . ), to the best of our knowledge, continuous cultivation of thermophilic bacteria for EPS production has not been reported.…”

Scaling-up the production of thermostable lipolytic enzymes from Thermus aquaticus YT1

“…Factors such as agitation-aeration, pH and temperature, as well as culture medium composition, exert a relevant influence on the production of lipases. Previous studies on lipolytic enzymes production by other thermophilic strains indicated that the process was strongly affected by cultivation variables, such as the mineral content of the culture medium and the degree of aeration amongst others [11][12][13][14]. However, the effects of operating variables on the production of microbial metabolites are strongly strain dependent, and it remains to be ascertained if T. aquaticus YT1 might show a similar behaviour to other Thermus strains.…”

“…In previous works with another Thermus strain, Fuciños et al [10] and Domínguez et al [13] concluded that the mineral composition of the culture medium is a key factor to take into account not only for microbial growth, but also for the production of lipolytic enzymes. High levels of lipolytic activity were obtained when mineral water from hot springs was employed.…”

“…Additionally, mineral water from a hot spring (As Burgas, Spain) was used instead of deionized water as described by Domínguez et al [13] (TB medium). Mineral water was directly collected from the source and subsequently cooled.…”