Full utilization of sweet sorghum for bacterial cellulose production: A concept of material crop

Abstract

In this work, the whole biomass of sweet sorghum [Sorghum bicolor (L.) Moench], including the sugar-rich juice and lignocellulosic parts (root, stalk, and leaf), was individually investigated as carbon sources for bacterial cellulose (BC) production. The juice part was employed directly, and the lignocellulosic parts were pretreated by PHP (phosphoric acid plus hydrogen peroxide) to yield the fermentable sugar for BC production. Results indicated that the BC yield from the root (2.28 g/L), stalk (1.82 g/L), and leaf (2.54 g/L) was 1.86–2.59-fold higher than the commercial d-glucose medium (0.98 g/L), and a comparable BC yield (0.87 g/L) also can be obtained from the juice. The structural properties of BC from the lignocellulosic parts were similar to those from the d-glucose medium. The tensile strength of BC obtained from the stalk and leaf was 8.24 MPa and 4.83 MPa, respectively, which was superior to that of the glucose medium (2.07 MPa). Considering the huge biomass yield of sweet sorghum, the present work broadens the “energy crop” sweet sorghum as a “material crop” towards a new biorefinery concept for material building blocks.