Biochemical and SSR based molecular characterization of elite rice varieties for straw lignocellulose.

BACKGROUND: Lignocellulosic biomass from rice straw possesses enormous potential in generating bioenergy thereby reducing the dependence of human on non-renewable fuel sources. Developing rice varieties of such calibre necessitates biochemical characterization as well as assessing the presence of genetic diversity among the rice genotypes with respect to cellulose content. METHODS AND RESULTS: Forty-three elite rice genotypes were selected for biochemical characterization and SSR marker-based genetic fingerprinting. For genotyping, 13 cellulose synthase specific polymorphic markers were used. The diversity analysis was performed using TASSEL 5.0 and GenAlE × 6.51b2, software program. Of the 43 rice varieties, CR-Dhan-601, CR-Dhan-1014, Mahanadi, Jagabandhu, Gouri, Samanta and Chandrama were found to possess desirable lignocellulosic composition with respect to harnessing green fuels. The marker OsCESA-1.3 expressed the highest PIC (0.640), while the marker OsCESA-6.3 of lowest PIC (0.128). A moderate average estimate (0.367) of PIC was observed under current set of genotypes and marker system. The dendrogram analysis grouped the rice genotypes into two principal clusters i.e., cluster I and II. Cluster-II is monogenetic, while cluster-I is having 42 genotypes. CONCLUSIONS: The moderate level of both PIC and H average estimates indicate the narrow genetic bases of the germplasms. The varieties falling under different clusters possessing desirable lignocellulosic composition can be used in a hybridization programme to develop bioenergy efficient varieties. The promising varietal combinations that can be used as parents for developing bioenergy efficient genotypes are Kanchan / Gobinda, Mahanadi / Ramachandi, Mahanadi / Rambha, Mahanadi / Manika, Rambha / Manika, Rambha / Indravati and CR-Dhan-601 / Manika as they offer an advantage of higher cellulose accumulation. This study helped in identification of suitable dual purpose rice varieties for biofuel production without compromising food security.

A comparative study on pyrolysis kinetics and thermodynamic parameters of little millet and sunflower stems biomass using thermogravimetric analysis.

Several biochemical and thermochemical routes including pyrolysis, liquefaction, combustion and gasification are used to convert biomass to several bioproducts and green fuels. The current investigation included two important biomass namely, little millet stem (LMS) and sunflower stem (SS), whose potentiality as useful feedstocks is largely unexplored. The presence of considerable level of cellulose accumulation (approx. 30 %), volatiles (approx. 67 %) and high heating value (approx. 14 MJ/kg) in both the biomass, inferred their potentiality to be used as feedstocks in the pyrolysis process. The estimate of activation energy for LMS was reported as 191.14 kJ/mol (FWO), 191.46 kJ/mol (KAS) whereas for SS, the activation energy was estimated as 166.52 kJ/mol (FWO) and 162.68 kJ/mol (KAS). The difference between change in enthalpy and activation energy was small (5 to 6 kJ/mol) for both the biomasses, indicating the feasibility of combustion process. From Z(α) analyses, the experimental curve was seen passing through different theoretical curves, indicating complex nature of pyrolysis process for both the biomass.