Biomass and bioenergy production potential of microalgae consortium in open and closed bioreactors using untreated carpet industry effluent as growth medium.

Improved wastewater management with beneficial utilization will result in enhanced sustainability and enormous cost savings in industries. Algae cultivation systems viz. raceway ponds, vertical tank reactors (VTR) and polybags were evaluated for mass production of algal consortium using carpet industry (CI) untreated wastewater. Overall areal biomass productivity of polybags (21.1 g m(-2)d(-1)) was the best followed by VTR (8.1 g m(-2)d(-1)) and raceways (5.9 g m(-2)d(-1)). An estimated biomass productivity of 51 and 77 tons ha(-1)year(-1) can be achieved using 20 and 30 L capacity polybags, respectively with triple row arrangement. Biomass obtained from algal consortium was rich in proteins (approximately 53.8%) and low in carbohydrates (approximately 15.7%) and lipids (approximately 5.3%). Consortium cultivated in polybags has the potential to produce 12,128 m(3) of biomethane ha(-1)year(-1). To be economically viable, the capital expenditure for polybag reactors needs to be reduced to $10 m(-2) for bioenergy/biofuel production.

Chloroplast monothiol glutaredoxins as scaffold proteins for the assembly and delivery of [2Fe-2S] clusters.

Glutaredoxins (Grxs) are small oxidoreductases that reduce disulphide bonds or protein-glutathione mixed disulphides. More than 30 distinct grx genes are expressed in higher plants, but little is currently known concerning their functional diversity. This study presents biochemical and spectroscopic evidence for incorporation of a [2Fe-2S] cluster in two heterologously expressed chloroplastic Grxs, GrxS14 and GrxS16, and in vitro cysteine desulphurase-mediated assembly of an identical [2Fe-2S] cluster in apo-GrxS14. These Grxs possess the same monothiol CGFS active site as yeast Grx5 and both were able to complement a yeast grx5 mutant defective in Fe-S cluster assembly. In vitro kinetic studies monitored by CD spectroscopy indicate that [2Fe-2S] clusters on GrxS14 are rapidly and quantitatively transferred to apo chloroplast ferredoxin. These data demonstrate that chloroplast CGFS Grxs have the potential to function as scaffold proteins for the assembly of [2Fe-2S] clusters that can be transferred intact to physiologically relevant acceptor proteins. Alternatively, they may function in the storage and/or delivery of preformed Fe-S clusters or in the regulation of the chloroplastic Fe-S cluster assembly machinery.