Nutrient effects on production of cellulolytic enzymes by Aspergillus niger

The production of cellulase (filter paper activity, endoglucanase and )-glucosidase) by Aspergillus niger on three media in liquid shake culture was compared. The culture filtrate of this organism exhibited relatively highest activity of all three enzymes and extracellular protein content at 7-day interval during the course of its growth on Czapek-Dox medium supplemented with 1.0% (w/v) cellulose. Urea as a nitrogen source and pH 5.0 were found to be optimal for growth and cellulase production by A.niger. Among various soluble organic carbon sources and lignocelluloses tested in this study, carboxymethylcellulose and sawdust at 1% supported maximum production of all three enzymes by A.niger.Keywords: Aspergillus niger, cellulase activity, nutrients, 6-glucosidas

Case studies on sugar production from underutilized woody biomass using sulfite chemistry

We examined two case studies to demonstrate the advantages of sulfite chemistry for pretreating underutilized woody biomass to produce sugars through enzymatic saccharification. In the first case study, we evaluated knot rejects from a magnesium-based sulfite mill for direct enzymatic sugar production. We found that the sulfite mill rejects are an excellent feedstock for sugar production. In the second study, we presented SPORL (sulfite pretreatment to overcome the recalcitrance of lignocelluloses), a sulfite pretreatment process based on modified sulfite pulping for robust bioconversion of softwood forest residues. Sulfite pulping technology is well developed, with proven commercial scalability, and sulfite pretreatment is a strong contender for commercial adoption. Application: Mills can consider sulfite chemistry, which has the advantage of high-yield sugar production from woody biomass through enzymatic saccharification.This is the publisher’s final pdf. The published article is copyrighted by Tappi Press and can be found at: http://www.tappi.org/tappijourna

Using sulfite chemistry for robust bioconversion of Douglas-fir forest residue to bioethanol at high titer and lignosulfonate: A pilot-scale evaluation

This study demonstrated at the pilot-scale (50 kg) use of Douglas-fir forest harvest residue, an underutilized forest biomass, for the production of high titer and high yield bioethanol using sulfite chemistry without solid–liquor separation and detoxification. Sulfite Pretreatment to Overcome the Recalcitrance of Lignocelluloses (SPORL) was directly applied to the ground forest harvest residue with no further mechanical size reduction, at a low temperature of 145°C and calcium bisulfite or total SO₂ loadings of only 6.5 or 6.6 wt% on oven dry forest residue, respectively. The low temperature pretreatment facilitated high solids fermentation of the un-detoxified pretreated whole slurry. An ethanol yield of 282 L/tonne, equivalent to 70% theoretical, with a titer of 42 g/L was achieved. SPORL solubilized approximately 45% of the wood lignin as directly marketable lignosulfonate with properties equivalent to or better than a commercial lignosulfonate, important to improve the economics of biofuel production.Keywords: High titer biofuel, Lignosulfonate, Pretreatment, Forest residues, Sulfite pulpin

Nutrient effects on production of cellulolytic enzymes by Aspergillus niger

The production of cellulase (filter paper activity, endoglucanase and β-glucosidase) by Aspergillus niger on three media in liquid shake culture was compared. The culture filtrate of this organism exhibited relatively highest activity of all three enzymes and extracellular protein content at 7day interval during the course of its growth on CzapekDox medium supplemented with 1.0% (w/v) cellulose. Urea as a nitrogen source and pH 5.0 were found to be optimal for growth and cellulase production by A.niger . Among various soluble organic carbon sources and lignocelluloses tested in this study, carboxymethylcellulose and sawdust at 1% supported maximum production of all three enzymes by A.niger

Cellulolytic Enzymes Production from Submerged Fermentation of Different Substrates by Newly Isolated Bacillus spp. FME

Newly isolated strains Bacillus sp. FME 1 and FME 2 were evaluated for the cellulolytic enzymes production during submerged fermentation (SmF) of different substrates including rice husk, Whatman filter paper and cellulose powder CF 11. Extracellular enzyme assays for CMCase, FPase and β-glucosidase were examined up to 8 days of submerged fermentation. Among the three substrates, rice husk was the most suitable substrate for higher production of cellulolytic enzymes. Maximum titers of 100, 45, and 3.5 U/mL in respect of CMCase, FPase and β-glucosidase in Bacillus sp. FME 2 were recovered as against 45, 12, and 0.39 U/mL in Bacillus sp. FME 1 respectively, at their respective peak time intervals. Bacillus sp. FME 2 was found to produce higher cellulolytic enzyme activities than Bacillus sp. FME 1

Molecular cloning, purification and characterization of thermostable <img src='/image/spc_char/beta.gif' border=0>-1,3-1,4 glucanase from <i>Bacillus subtilis </i>A8-8

203-210A gene encoding a -1,3-1,4-glucanase (CelA) belonging to family 5 of glycoside hydrolases was cloned and sequenced from the Bacillus subtilis A8-8. The open-reading-frame of celA comprised 1499 base pairs and the enzyme was composed of 500 amino acids with a molecular mass of 55 kDa. The recombinant -1,3-1,4 glucanase was purified by GST-fusion purification system. The pH and temperature optima of the enzyme were 8.0 and 60oC, respectively. The enzyme was stable within pH 6.0-9.0. It was stable up to 60oC and retained 30% of its original activity at 70oC for 60 min. It hydrolyzed lichenan, CMC, xylan, laminarin, avicel and pNPC, but was inactive towards cellobiose. The enzyme activity was markedly activated by Co2+ and Mn2+, but was strongly inactivated by Fe3+. The truncated gene, devoid of cellulose-binding domain (CBD) showed 60% of activity and bound to avicel