Authors: Subir Kundu, Sukhendra Singh, Ipsita Chakravarty and Kanika Kundu
Abstract: In the current scenario, the search of economically viable clean fuels is a major issue. Several researches are going all around the world to find alternative fuels to tackle green house effect and global warming. Bioethanol and biohydrogen are the current stars of alternative fuels. Several efforts are being taken to convert environmental wastes into useful substrates for bioethanol and biohydrogen production. There is a great problem of pollution of our water bodies in India. Bioethanol is an excellent alternative for petrol and has long-term economic advantages over non-renewable liquid biofuels. Bioethanol can be produced from different biomass materials, and it is categorized into three generations by biomass. Algae have higher growth rates than plants and require less land area also they do not need additional fertilizers for their growth. Microalgae can fix atmospheric CO2 from the environment and assimilate it into lipid and carbohydrates which can be used as a substrate for biofuel production. Microalgae Chlorella sp. was cultivated at 28oC and light intensity of 60 μmol m-2 s-1 and used as a source of starch for bioethanol production. Chlorella starch was hydrolyzed into fermentable sugars by amylases produced from Aspergillus niger NCIM 616 for bioethanol production by yeast Saccharomyces cerevisiae NCIM 3494. Microbial growth, reducing sugar consumption, and bioethanol production were described quantitatively. Another problem is temple floral and leaf waste being discarded in the holy rivers and around the temples due to religious beliefs. Treatment of the temple waste for production of hydrogen is a method to check this kind of pollution of Holy Rivers. Nelubmo nucifera (Lotus) flowers, Jacaranda mimosifolia (Neelkanth) flowers, Tithonia diversifolia (Marigold) flowers and Limonia acidissima (Bel) leaves were collected from various temples of Varanasi and used as substrate for hydrogen production in the present study. Among the flower and leaves waste, the flower waste acid hydrolysate obtained from Jacaranda mimosifolia showed good potential for hydrogen production and it produces 310 ml of hydrogen in 96 hours which is higher than Tithonia diversifolia, Nelubmo nucifera and Limonia acidissima.