or sugar-derived compounds were used as environmentally friendly additives for the depolymerization of Kraft lignin waste and organosolv lignin prepared from Miscanthus giganteus. The yields of the aromatic monomers obtained from Kraft lignin increased from 5.1 to 49.2% with the addition of mannitol, while those obtained from organosolv lignin increased from 44.4 to 83.0% with the addition of sucrose. This improved lignin depolymerization was also confirmed by gel permeation chromatography and nuclear magnetic resonance spectroscopy. The above results clearly indicate the beneficial effects of carbohydrate derivatives on the lignin depolymersization process, more specifically, suggesting that the presence of carbohydrates improve the lignin depolymerization of lignocellulose, as observed for the raw lignocellulose feed.

The aim of this study was to characterize qualitatively and quantitatively the composition of the main rhizodeposits emitted from maize (Zea mays) under Cd stress, in order to discuss their role in Cd availability and tolerance. Maize was grown for 6weeks in sand at four Cd exposure levels (0, 10, 20, and 40M Cd in nutrient solution) and two types of rhizodeposits were collected at the end of cultivation period. Mucilage and other molecules adhering to rhizospheric sand were extracted with a buffer before root exudates were collected by diffusion into water. Total carbon, proteins, amino acids, and sugars were analyzed for both rhizodeposit types and about 40 molecules were identified using GC-MS and LC-MS. Cadmium effect on plant morphology and functioning was slight, but consistent with previous works on Cd toxicity. However, rhizodeposition did tend to be impacted, with a decrease in total carbon, sugars, and amino acids correlating with an increasing Cd content. Such a decrease was not noticeable for proteins in root exudates. These observations were confirmed by the same trends in individual compound contents, although the results were generally not statistically significant. Many of the molecules determined are well-known to modify, whether directly or indirectly, Cd speciation and dynamics in the soil and could play a role in Cd tolerance.

To expand the range of soluble carbon sources for enzyme production by the microbial system, we investigated the ability of different sugars in cellulase production. Carbon sources play a vital role in cell metabolism and the synthesis of cellulase. Although the insoluble cellulosic materials are considered the most effective natural inducers for cellulase production by microorganisms in terms of both enzyme yield and productivity, their insolubility causes many problems and presents a major drawback that is partly responsible for the high cost of cellulase production. Mostly, the insolubility of sugar polymer leads to difficult and complex fermentation operations, including sterilization, cell biomass measurement, mixing and aeration of the fermentation broth, continuous feeding/sampling, and subsequent enzyme purification. Second, cellulase gets absorbed into the solid cellulose surface, leading to enzyme loss. The present paper gives a comparative view on the utility of pure sugars (lactose, CMC, sucrose, maltose, cellobiose, xylose, trehalose, arabinose) and sugar alcohols (sorbitol, mannitol) on cellulase production by various fungal strains. It also describes the blending effect of sugars as well as sugar alcohols on cellulase production by fungal strains.