Genotype contribution to the chemical composition of banana rachis and implications for thermo/biochemical conversion

Abstract

Chemical composition of banana rachis from three varieties (Grande naine, Pelipita, and CRBP969) was analyzed, and the genotype contribution to composition variability was investigated. Wet chemistry and instrumental analysis procedures (X-ray diffraction, 31P NMR spectroscopy, and thermogravimetry) were used. Some significant differences were found among the three genotypes: GN-AAA genotype was found to be significantly the highest in ash fraction (30.16 %) and the lowest in acid insoluble lignin (6.58 %) at 95 % confidence level. It showed also the highest content in potassium (43.5 % in ash). Implication of compositional differences on valorization efficiency by biochemical or thermochemical pathways was investigated. For this purpose, correlation coefficients between compositional characteristics and yields in volatile compounds from pyrolysis and glucose yields from enzymatic saccharification were analyzed. Ash content was revealed to be the main drawback parameter for volatile yields from pyrolysis (r = −0.93), while for glucose yields during saccharification were limited mainly by the content in guaiacyl units of the lignin fraction (r = −0.98). However, a strong and positive correlation was established between the volatiles yield and the acid insoluble lignin content (r = 0.98) Thus, according to these observations and based on their compositional significant differences, GN-AAA was the better candidate for bioconversion pathway while PPT-ABB and CRBP969-AAAB samples were shown to be better candidates for thermochemical conversion pathway. This work gives important preliminary information for considering banana rachis as an interesting feedstock candidate for biorefinery.