In the transportation sector, the most commonly used biofuel is 'bioethanol' to reduce greenhouse gases. Ethanol production at the industrial level is employed by many yeast, bacteria, and fungi. But Saccharomyces Cerevisiae is most employed yeast. Wide range of substrates has been used for ethanol production such as lignocellulose, molasses, sweat sorghum cane extract, starch based substrate and other wastes. Lignocellulosic hydrolysates contain many inhibitors that can be reduced by treatment with activated charcoal and reducing agents, repeated sequential fermentation, over-liming, evaporation, anion exchanger, enzymatic treatment using peroxidase and laccase, and in-situ detoxification with fermenting microbes. Co-culturing of S. Cerevisiae with other microbes is targeted for optimization of ethanol production, short fermentation time, and for reduced process cost. Yeast cell immobilization has been considered as a potential alternative to enhance ethanol productivity. This paper also reviews the effects of various factors on yeast fermentation for ethanol optimization.

Heavy metal contamination due to natural and anthropogenic sources is a global environmental threat which can produce harmful effects on human health when they are taken up in amounts that cannot be processed by the organism. Technologies involving microbial cells for metal removal and recovery may provide an alternative to conventional methods. In the present study, three cadmium resistant bacteria were isolated from soil collected from industrial area of Faridabad, Haryana, India. Screening of the bacterial isolates for metal resistance against Cd2+, Ni2+, Hg2+, Cu+2 and Pb2+ was done by determining the minimal inhibitory concentration ranging from 10ppm to 250ppm. Moreover these isolates showed a significant ability to remove 70 to 78% of cadmium. These isolates were identified as Bacillus sp.263ZY1 (MA5), Bacterium YC-LK-LKJ45 (MB5) and Bacillus subtilis strain DHXJ07(MC5) on the basis of 16S r-RNA gene sequencing. The ability of these microbes to tolerate high concentration of a range of heavy metals provides a scope of use of these bacterial strains for bioremediation of heavy metal from industrial effluent.