How to Determine the Efficiency of Biomass Pretreatment Processes

Biobutanol has gained attention as an alternative renewable transportation fuel for its superior fuel properties and widespread applications in chemical industry, primarily as a solvent. Conventional butanol fermentation has drawbacks that include strain degeneration, end-product toxicity, by-product formation, low butanol concentrations and high substrate cost. The complexity of Clostridium physiology and close control between sporulation phase and ABE fermentation has made it demanding to develop industrially potent strains. In addition to the isolation and engineering of superior butanol producing bacteria, the development of advanced cost-effective technologies for butanol production from feedstock like lignocellulosic biomass has become the primary research focus. High process costs associated with complex feedstocks, product toxicity and low product concentrations are few of the several bioprocess challenges involved in biobutanol production. The article aims to assess the challenges in lignocellulosic biomass to biobutanol conversion and identify key process improvements that can make biobutanol commercially viable.

The present study was carried out to evaluate the antioxidant and antibacterial activity of lichen Xanthoparmelia somloensis, native to the Black Hills in South Dakota, USA. The antioxidant activity of lichen extracts was assessed using the 1,1-diphenyl-2-picrylhydrazyl free radical scavenging assay. The lipid peroxidation reaction of acetone and methanol extracts was inhibited 85% and 81%, respectively A free radical scavenging activity of 77% (acetone extract) and 65% (methanol extract) was determined. The antibacterial activity was assayed against four clinical strains using the agar well diffusion method. Except for Escherichia coli, both extracts were found inhibitory to Streptomyces aureus, Streptococcus pyogenes,and Steptococcus agalactiae with minimum inhibitory concentration values of 0.7-0.9 mg/ml. It was demonstrated that both the antioxidant and antibacterial activities correlated well with the protein to polysaccharide ratio rather than the polyphenol content of the lichen extracts. To the best of our knowledge, this is the first literature report on antibacterial activity from the lichen X.somloensis. The results reported here warrant further investigations to establish the usefulness of X.somloensis in biomedical applications such as treatment of respiratory and urinary tract infections.

Rice straw is an attractive lignocellulosic material for bioethanol production since it is one of the most abundant renewable resources. It has several characteristics, such as high cellulose and hemicelluloses content that can be readily hydrolyzed into fermentable sugars. But there occur several challenges and limitations in the process of converting rice straw to ethanol. The presence of high ash and silica content in rice straw makes it an inferior feedstock for ethanol production. One of the major challenges in developing technology for bioethanol production from rice straw is selection of an appropriate pretreatment technique. The choice of pretreatment methods plays an important role to increase the efficiency of enzymatic saccharification thereby making the whole process economically viable. The present review discusses the available technologies for bioethanol production using rice straw.