Hydrogen productivity of photosynthetic bacteria on dark fermenter effluent of potato steam peels hydrolysate

Integrative Biological Hydrogen Production: An Overview

“…In dark-fermentative BHP, the H 2 yields are quite low in most cases and exceptionally it is posible to achieve a value of 3.8 mol H 2 /mol hexose [57]. In contrast, the two stage integrative approach is much more effective and exceptionally only it falls around 2.8-3.9 mol/mol hexose [45,51,58]. A summary of the results of yields of C7.0 mol H 2 /mol hexose reveals that it has been achieved with combinations such as (i) mixed culture-R. palustris and water hyacinth (10 g/l) [33], (ii) Clostridium butyricum-R. sphaeroides-algal biomass (starch at the rate of 5 g/l) [31], (iii) C. butyricum and Enterobacter aerogenes-R. sphaeroides/Rhodobacter sp.…”

“…The intermediates of the dark-fermentative BHP, such as acetic and butyric acid can be taken up by photosynthetic organisms to generate additional H 2 (Eqs. [5][6] [45,46,50,51] …”

“…Instead of dwelling on optimization efforts being made on individual parameters of BHP process, an emerging proposal is to combine the dark-and photofermentative H 2 producing organisms [7,10,35,36]. The efforts in this direction have been targeted on the following combinations: (i) using defined dark-and photo-fermentative H 2 producing organisms in a sequential manner in two independent stages (ii) using undefined dark-fermentative H 2 -producers along with defined photosynthetic organisms in two stages (iii) using the two types of BHP processes into a single stage, and (iv) using effluent from a dark-fermentative process (not necessarily a H 2 production reactor) and exploiting photo-fermentative bacteria for their H 2 producing abilities [33,[37][38][39][40][41][42][43][44][45][46][47][48]. In our recent efforts, we have emphasized only on using defined bacterial cultures in a sequential manner and evaluate it with respect to their individual H 2 producing abilities from pure substrates and biowastes [7].…”

Photofermentative Hydrogen Production in Outdoor Conditions

“…Moreover, they can also use sugar containing wastes derived from various industries such as the tofu industry wastewater [129], olive mill wastewater [132], sugar refinery wastewater [133], dairy wastewater [134], palm oil mill wastewater [135] and ground wheat starch [136]. Effluents from dark fermentation have also been applied in several studies [54,55,66,106,[137][138][139].…”

“…Rhodobacter sphaeroides O.U.001 was found to initially deplete acetate, then propionate and butyrate [138]. R.capsulatus was found to initially consume lactic acid then acetic acid in a study using a mixture of the organic acids [59].…”