Estimation of Energy Cane Lignocellulosic Composition Using Near Infrared Spectroscopy.

Lignocellulosic composition in energy cane biomass is an important source of fermentable sugars for biofuel production. The standard method for quantification of biomass lignocellulosic composition involves long and complex procedures. Successful use of near infrared (NIR) spectroscopy for chemical analysis of soil and plant samples has been document, however, very little is known about its potential use for rapid and instant biomass compositional analysis of lignocellulosic-rich crops such as energy cane. A laboratory experiment was conducted to calibrate lignocellulosic composition analysis between two methods: ANKOM²⁰⁰⁰ and NIR spectroscopy. Fifteen whole plants were collected from research plots planted to cane and treated with different nitrogen rates. Plants were separated (into leaves and stalks), processed and analyzed for lignocellulosic composition. Regression analysis showed that absorbance readings from wavebands between 450 and 800 nm produced positive linear relationship with stalk lignin composition obtaining the highest r² of 0.32 with absorbance reading at 519 nm. Negative linear relationship exist between stalk cellulose composition and absorbance readings from wavebands between 400 and 800 nm with the highest r²= 0.26 at 519 nm. Hemicellulose content  generally had  weak, positive linear relationships  with absorbance reading at different wavebands between 500-600 and 750-800 nm; the highest r² values of 0.13 and 0.19 were obtained at 519 nm for leaf and stalk samples, respectively. Selected wavebands from visible and near infrared bands showed promise but continuous data collection is required to build a strong database to establish the models that will be used for NIR spectroscopy-based lignocellulosic compositional analysis.