Xylanase and feruloyl esterase from actinomycetes cultures could enhance sugarcane bagasse hydrolysis in the production of fermentable sugars.

The addition of enzymes that are capable of degrading hemicellulose has a potential to reduce the need for commercial enzymes during biomass hydrolysis in the production of fermentable sugars. In this study, a high xylanase producing actinomycete strain (Kitasatospora sp. ID06-480) and the first ethyl ferulate producing actinomycete strain (Nonomuraea sp. ID06-094) were selected from 797 rare actinomycetes, respectively, which were isolated in Indonesia. The addition (30%, v/v) of a crude enzyme supernatant from the selected strains in sugarcane bagasse hydrolysis with low-level loading (1 FPU/g-biomass) of Cellic® CTec2 enhanced both the released amount of glucose and reducing sugars. When the reaction with Ctec2 was combined with crude enzymes containing either xylanase or feruloyl esterase, high conversion yield of glucose from cellulose at 60.5% could be achieved after 72 h-saccharification.

Pretreatment with dilute maleic acid enhances the enzymatic digestibility of sugarcane bagasse and oil palm empty fruit bunch fiber.

Lignocellulose is resistant to degradation and requires pretreatment before hydrolytic enzymes can release fermentable sugars. Sulfuric acid has been widely used for biomass pretreatment, but high amount of degradation products usually occurred when using this method. To enhance accessibility to cellulose, we studied the performances of several dilute organic acid pretreatments of sugarcane bagasse and oil palm empty fruit bunch fiber. The results revealed that pretreatment with maleic acid yields the highest xylose and glucose release among other organic acids. The effects of concentration, duration of heating and heating temperature were further studied. Dilute maleic acid 1 % (w/w) pretreatment at 180 °C was the key to its viability as a substitute for sulfuric acid. Moreover, maleic acid did not seem to highly promote the formation of either furfural or 5-HMF in the liquid hydrolysate after pretreatment.

Improvement of microwave-assisted hydrolysis of cassava pulp and tapioca flour by addition of activated carbon.

The superior effects of addition of activated carbon were evidenced for microwave assisted hydrolysis of starches in cassava pulp and tapioca flour under hydrothermal conditions varying irradiation temperature (160-230°C at 5min), duration of heating time (5-18min at 210°C) and amount of activated carbon at 0.5-2.0:1:20 of activated carbon:solid:liquid ratio. The presence of 1.0g/g in microwave-assisted hydrolysis gave much improved glucose yields (44.49% for cassava pulp and 71.93% for tapioca flour) at lower heating temperature (220°C and 200°C, each for 5min) with suppressed formation of secondary decomposed compounds than those without addition of activated carbon (32.41% in cassava pulp at 230°C and 55.11% in tapioca flour at 240°C, each for 5min). The highest glucose yield from cassava pulp (52.27%) was obtained after heating at 210°C for 15min.