Hydrogen peroxide bleaching of cellulose pulps obtained from brewer’s spent grain

Brewer’s spent grain (BSG) was evaluated for bleached pulp production. Two cellulose pulps with different chemical compositionswere produced by soda pulping: one from the original raw material and the other from material pretreated by dilute acid. Both of them were bleached by a totally chlorine-free sequence performed in three stages, using 5% hydrogen peroxide in the two initial, and a 0.25 NNaOHsolution in the last one. Chemical composition, kappa number, viscosity, brightness and yield of bleached and unbleached pulps were evaluated. The high hemicellulose (28.4% w/w) and extractives (5.8% w/w) contents in original BSG affected the pulping and bleaching processes.However, soda pulping of acid pretreated BSG gave a celluloserich pulp (90.4% w/w) with low hemicellulose and extractives contents (7.9% w/w and <3.4% w/w, respectively), which was easily bleached achieving a kappa number of 11.21, viscosity of 3.12 cp, brightness of 71.3%, cellulose content of 95.7% w/w, and residual lignin of 3.4% w/w. Alkaline and oxidative delignification of acid pretreated BSG was found as an attractive approach for producing high-purity, chlorine-free cellulose pulp.FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo), Brazil.CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico).Capes (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior)

Recent Advances in Sugarcane Industry Solid By-Products Valorization

Sugarcane is among the leading agricultural crop cultivated in tropical regions of the world. Industrial processing of sugarcane generates sugar; as well as various solid wastes (i.e. sugarcane bagasse, pressmud). Improvement of biotechnology in industrial level, offers opportunities for economic utilization of these solid residues. In the last few decades, sugarcane bagasse and pressmud have been explored in the theme of lignocellulosic bioconversion. The recalcitrance of biomass is a major drawback towards successful exploitation of lignocellulosic residues. Pretreatment by suitable/efficient processes can overcome this limitation. In this regards; physical, chemical and biological treatment systems are brought into our perspective. Chemical and physicochemical methods are capital-intensive but not environment-friendly, in contrast, method like biological treatment is eco-friendly but extremely slow. There are still major technological and economic challenges need to be addressed; e.g. bioprospecting, established more reliable genetically modified microorganisms, upgrade gene cloning and sequencing processes, yield improvement at large scale etc. Productions of value-added products from these solid wastes are discussed in such a way that pinpoints the most recent trends and the future directions. Biofuels, enzymes, organic acids and bio-sorbents production draw a clear sketch of the current and future bio-based products. Nano-biotechnology and genetic engineering could be future trends to improved processes and products. This review serves as a valuable reference material for a wide range of scientists and technologists in the relevant fields