Optimized A. niger saccharifies pre-treated wheat straw

TL;DR

Wheat Straw Saccharification: Researchers optimized enzymatic breakdown of alkali-pre-treated wheat straw using Aspergillus niger to produce sugars.[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511)
Peak Sugar Yield: Reducing sugar reached 92.4 mg/g dry substrate under optimal solid-state fermentation conditions.[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511)
Matrix Destruction Confirmed: Analyses showed complete disruption of lignocellulosic structure after fungal treatment.[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511)

The story at a glance

Mostafa M. El-Sheekh and colleagues at Tanta University and the National Research Center in Egypt report on selecting Aspergillus niger (GeneBank MZ062603) from 30 fungal isolates for high cellulase production to saccharify pre-treated wheat straw. They compared acid, alkali, and hot-water pre-treatments, finding 1% NaOH best, which boosted total cellulase activity 2.8-fold and reducing sugars 3.1-fold during solid-state fermentation. This lab study advances low-cost bioconversion of lignocellulosic waste, published online June 15, 2022, in Biocatalysis and Biotransformation.[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511)

Key points

Among 30 local fungal isolates, A. niger produced the highest cellulase levels and was deposited as MZ062603 in GeneBank.[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511)
Pre-treatments tested: acid (0-0.7%), alkali (0-2% NaOH), hot water (70-90°C); 1% NaOH on wheat straw proved superior for digestibility.[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511)
Solid-state fermentation optimized at 30°C, pH 5.2, 75% v/w moisture, 3-day-old inoculum (10^6 spores/mL/g dry substrate), yielding peak cellulases at 8907.2 mg/g dry substrate after 3 days.[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511)
Total cellulolytic enzymes—filter paper cellulase (FPase), CMCase, β-glucosidase—increased 2.8-fold; reducing sugars rose 3.1-fold versus untreated.[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511)
Post-treatment wheat straw showed changed chemical composition and structure per SEM, FTIR, and XRD, confirming lignocellulosic matrix destruction.[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511)

Details and context

The study targets bioconversion of lignocellulosic wastes like wheat straw into sugars for biofuels or chemicals via multi-enzyme hydrolysis, a process seen as low-cost for industry. Wheat straw's tough matrix resists breakdown, so pre-treatment exposes cellulose; alkali here swelled fibers best, aiding fungal enzyme access.[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511)

Optimization used solid-state fermentation on pre-treated straw, mimicking natural decay but controlled for max enzyme output. Analyses like scanning electron microscopy revealed surface pitting, while FTIR and XRD showed lost crystallinity—direct evidence of degradation.[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511)

Funding came partly from the Egyptian Academy for Scientific Research and Technology for one researcher's MSc; no conflicts reported, all data in the paper.[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511)

Key quotes

No direct quotes from authors beyond abstract and metadata.

Why it matters

Efficient lignocellulosic bioconversion supports biofuel production from agricultural waste, reducing reliance on food crops and fossil fuels. For researchers and industry, it offers a benchmark protocol with 92.4 mg/g sugar yield using cheap fungal enzymes on alkali-treated straw.[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511) Scale-up could lower costs, but pilot tests are needed to confirm industrial viability.

What changed

No prior state described.

FAQ

Q: What pre-treatment worked best for wheat straw?[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511)

A: 1% NaOH pre-treatment outperformed acid (0-0.7%) and hot water (70-90°C), enhancing digestibility by A. niger enzymes. It prepared straw for solid-state fermentation where cellulase activity rose 2.8-fold.

Q: What were the optimal fermentation conditions?[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511)

A: Incubation for 3 days at 30°C and pH 5.2 with 75% v/w moisture using 3-day-old A. niger inoculum at 10^6 spores/mL/g dry substrate. This gave 8907.2 mg/g total cellulases and 92.4 mg/g reducing sugar.

Q: How was lignocellulosic breakdown confirmed?[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511)

A: Chemical analysis showed composition shifts; SEM displayed structural damage, FTIR indicated bond changes, and XRD revealed reduced crystallinity. These proved complete matrix destruction post-fungal treatment.

Q: Which fungus was selected and why?[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511)

A: A. niger from 30 local isolates for highest cellulase production, identified as MZ062603 in GeneBank. It excelled in hydrolyzing pre-treated straw into sugars.

[[1]](https://www.tandfonline.com/doi/abs/10.1080/10242422.2022.2087511)