Effect of lignocellulosic composition and structure on the bioethanol production from different poplar lines

A sequential pretreatment of lignocelluloses in bamboo biomass to fermentable sugars by acid/enzymatic hydrolysis

A sequential pretreatment method for hydrolyzing rigid hemicelluloses and cellulose content in the bamboo biomass was investigated in this study. The effects of different parameters, such as nature of biomass, type of acid, acid and biomass concentration, were studied. Under the optimum condition of 5% (v/v) HCl-treated biomass and biomass concentration (8%, w/v), the maximum yield of sugar (619 mg/g of biomass) was obtained. The enzymatic hydrolysis parameter conditions were further optimized by response surface methodology-based central composite method. According to the results, the highest yield of sugar (515 mg/g of biomass) was obtained at hydrolysis temperature 50 °C, biomass concentration 8.9%, w/v, enzyme concentration (199.8 mg/g of biomass) and time 60 h, respectively. The effects of untreated, pretreated and enzymatically hydrolyzed biomass structure and complexity were investigated by field emission scanning electron microscopy and X-ray diffraction techniques.

Pretreatment and conversion of lignocellulose biomass into valuable chemicals

Lignocellulose biomass can be utilized in many sectors of industry such as energy, chemical, and transportation. However, pretreatment is needed to break down the intricate bonding before converting it into wanted product.

Solar assisted alkali pretreatment of garden biomass: Effects on lignocellulose degradation, enzymatic hydrolysis, crystallinity and ultra-structural changes in lignocellulose

A comprehensive study was carried out to assess the effectiveness of solar assisted alkali pretreatment (SAAP) on garden biomass (GB). The pretreatment efficiency was assessed based on lignocellulose degradation, conversion of cellulose into reducing sugars, changes in the ultra-structure and functional groups of lignocellulose and impact on the crystallinity of cellulose, etc. SAAP was found to be efficient for the removal of lignin and hemicellulose that facilitated enzymatic hydrolysis of cellulose. FTIR and XRD studies provided details on the effectiveness of SAAP on lignocellulosic moiety and crystallinity of cellulose. Scanning electron microscopic analysis showed ultra-structural disturbances in the microfibrils of GB as a result of pretreatment. The mass balance closer of 97.87% after pretreatment confirmed the reliability of SAAP pretreatment. Based on the results, it is concluded that SAAP is not only an efficient means of pretreatment but also economical as it involved no energy expenditure for heat generation during pretreatment.

Evaluation of recalcitrant features impacting enzymatic saccharification of diverse agricultural residues treated by steam explosion and dilute acid

Exploring agricultural biomass for biofuel production necessitates pretreatment as a prerequisite step.

2G ethanol from the whole sugarcane lignocellulosic biomass

BACKGROUND

In the sugarcane industry, large amounts of lignocellulosic residues are generated, which includes bagasse, straw, and tops. The use of the whole sugarcane lignocellulosic biomass for the production of second-generation (2G) ethanol can be a potential alternative to contribute to the economic viability of this process. Here, we conducted a systematic comparative study of the use of the lignocellulosic residues from the whole sugarcane lignocellulosic biomass (bagasse, straw, and tops) from commercial sugarcane varieties for the production of 2G ethanol. In addition, the feasibility of using a mixture of these residues from a selected variety was also investigated.

RESULTS

The materials were pretreated with dilute acid and hydrolyzed with a commercial enzymatic preparation, after which the hydrolysates were fermented using an industrial strain of Saccharomyces cerevisiae. The susceptibility to enzymatic saccharification was higher for the tops, followed by straw and bagasse. Interestingly, the fermentability of the hydrolysates showed a different profile, with straw achieving the highest ethanol yields, followed by tops and bagasse. Using a mixture of the different sugarcane parts (bagasse-straw-tops, 1:1:1, in a dry-weight basis), it was possible to achieve a 55% higher enzymatic conversion and a 25% higher ethanol yield, compared to use of the bagasse alone. For the four commercial sugarcane varieties evaluated using the same experimental set of conditions, it was found that the variety of sugarcane was not a significant factor in the 2G ethanol production process.

CONCLUSIONS

Assessment of use of the whole lignocellulosic sugarcane biomass clearly showed that 2G ethanol production could be significantly improved by the combined use of bagasse, straw, and tops, when compared to the use of bagasse alone. The lower susceptibility to saccharification of sugarcane bagasse, as well as the lower fermentability of its hydrolysates, can be compensated by using it in combination with straw and tops (sugarcane trash). Furthermore, given that the variety was not a significant factor for the 2G ethanol production process within the four commercial sugarcane varieties evaluated here, agronomic features such as higher productivity and tolerance of soil and climate variations can be used as the criteria for variety selection.