Photoheterotrophic cultivation of purple non-sulphur bacterium Rhodovulum adriaticum on the media with different carbon sources

Ljubičaste nesumporne bakterije zanimljive su s ekološkog i ekonomskog stajališta u održivim biotehnološkim procesima proizvodnje biogoriva, biokemikalija, biopolimera, biomase odnosno sintezi specifičnih spojeva kao što su npr. karotenoidi i pigmenti. Za uspostavu ekološki i ekonomski održivih bioprocesa nužan je adekavatan odabir radnih mikroorganizama, sirovina i uvjeta kultivacije, a dobar primjer za to je razvoj bioprocesa na obnovljivim sirovinama kao što su to lignocelulozne sirovine. U ovom istraživanju proučavan je fotoheterotrofni uzgoj ljubičaste nesumporne bakterije Rhodovulum adriaticum DSM 2781 na tekućim hranjivim podlogama koje sadrže glukozu i/ili ksilozu kao izvore ugljika s ciljem dobivanja bakterijske biomase i fotosintetskih pigmenata. Rezultati istraživanja pokazuju da su najveće vrijednosti pokazatelja uspješnosti bioprocesa (YX = 2,095 g L-1; YX/S = 0,54 g g-1i Pr = 0,022 g L-1h-1) vezanih u dobivanje biomase ostvareni kod uzgoja na hranjivoj podlozi s 5 g L-1 glukoze. Uzgoj R. adriaticum DSM 2781 na hranjivoj podlozi s 3 g L-1 glukoze i ksiloze pokazao se najuspješnji za dobivanje fotosintetskih pigmenata (ukupni pigmenti 13,27 mg g-1 biomase) uz zadovoljavajuće ostale pokazatelje uspješnosti bioprocesa (YX = 1,507 g L-1; YX/S = 0,22 g g-1i Pr = 0,017 g L-1h-1).Purple non-sulphur bacteria are interesting from ecologic and economic point of view in sustainable biotechnological production of biofuels, biochemicals, biopolymers and biomass as well as specific compounds such as carotenoids and pigments. In order to establish ecological and economic sustainable bioprocesses it is necessary to select adequate working microorganisms, raw materials and cultivation conditions. Development of bioprocesses on the renewable raw materials (e.g. lignocellulose containing feedstocks) are good example for such bioprocess types. In this research, the photoheterotrophic cultivation of purple non-sulfur bacteria Rhodovulum adriaticum DSM 2781 was studied on the liquid media containing glucose or /and xylose as a carbon sources in order to produce bacterial biomass and photosynthetic pigments. Results obtained in this study show that the highest values of bioprocess efficiency parameters (YX = 2,095 g L-1; YX/S = 0,54 g g-1i Pr = 0,022 g L-1h-1) related to the biomass production were observed during bacterial cultivation on media with 5 g L-1. Cultivation of R. adriaticum DSM 2781 on the media with 3 g L-1 glucose and xylose shows the highest total photosynthetic pigments content (13,27 mg g-1 biomass) together with satisfy other bioprocess efficiency parameters (YX = 1,507 g L-1; YX/S = 0,22 g g-1i Pr = 0,017 g L-1h-1)