Catalytic hydrolysis of cellobiose using different acid-functionalised Fe3O4 magnetic nanoparticles.

The present study demonstrated the preparation of three different acid-functionalised magnetic nanoparticles (MNPs) and evaluation for their catalytic efficacy in hydrolysis of cellobiose. Initially, iron oxide (Fe3O4)MNPs were synthesised, which further modified by applying silica coating (Fe3O4-MNPs@Si) and functionalised with alkylsulfonic acid (Fe3O4-MNPs@Si@AS), butylcarboxylic acid (Fe3O4-MNPs@Si@BCOOH) and sulphonic acid (Fe3O4-MNPs@Si@SO3H) groups. The Fourier transform infrared analysis confirmed the presence of above-mentioned acid functional groups on MNPs. Similarly, X-ray diffraction pattern and energy dispersive X-ray spectroscopy analysis confirmed the crystalline nature and elemental composition of MNPs, respectively. TEM micrographs showed the synthesis of spherical and polydispersed nanoparticles having diameter size in the range of 20-80 nm. Cellobiose hydrolysis was used as a model reaction to evaluate the catalytic efficacy of acid-functionalised nanoparticles. A maximum 74.8% cellobiose conversion was reported in case of Fe3O4-MNPs@Si@SO3H in first cycle of hydrolysis. Moreover, thus used acid-functionalised MNPs were magnetically separated and reused. In second cycle of hydrolysis, Fe3O4-MNPs@Si@SO3H showed 49.8% cellobiose conversion followed by Fe3O4-MNPs@Si@AS (45%) and Fe3O4-MNPs@Si@BCOOH (18.3%). However, similar pattern was reported in case of third cycle of hydrolysis. The proposed approach is considered as rapid and convenient. Moreover, reuse of acid-functionalised MNPs makes the process economically viable.

Utilization of sugarcane straw for production of ß-glucan biopolymer by Lasiodiplodia theobromae CCT 3966 in batch fermentation process.

ß-Glucans as emerging biopolymer are widely produced by microorganisms in fermentation processes using commercial sugars which make process non-economic. Lignocellulosic substances are inexpensive carbon sources, which could be exploited for sustainable production of ß-glucans. In this study, a lignocellulosic material, namely sugarcane straw (SCS) was utilized for the production of extracellular ß-glucan by Lasiodiplodia theobromae CCT3966. SCS was subjected to acid and subsequent alkaline pretreatment, followed by enzymatic saccharification using cellulase enzyme. Quantity of 48.65 g/L glucose was released after enzymatic hydrolysis. ß-Glucan production was performed by cultivation of fungal strain in SCS hydrolysate at 28 °C and initial culture pH 7. Highest ß-glucan yield and productivity of 0.047 gg-1 and 0.014 gL-1h-1, respectively was obtained at 72 h fermentation time. Kinetic study of ß-glucan production revealed experimental biosynthesis of ß-glucan from SCS hydrolysate followed the trend generated by Logistic and Luedeking-Piret models. Chemical structure of biopolymer produced showed ß-glucan constitution.