Optimization of sulfide/sulfite pretreatment of lignocellulosic biomass for lactic acid production.
Potential of sodium sulfide and sodium sulfite, in the presence of sodium hydroxide was investigated to pretreat the corncob (CC), bagasse (BG), water hyacinth and rice husk (RH) for maximum digestibility. Response Surface Methodology was employed for the optimization of pretreatment factors such as temperature, time and concentration of Na₂S and Na₂SO₃, which had high coefficient of determination (R²) along with low probability value (P), indicating the reliable predictability of the model. At optimized conditions, Na₂S and Na₂SO₃ remove up to 97% lignin, from WH and RH, along with removal of hemicellulose (up to 93%) during pretreatment providing maximum cellulose, while in BG and CC; 75.0% and 90.0% reduction in lignin and hemicellulose was observed. Saccharification efficiency of RH, WH, BG and CC after treatment with 1.0% Na₂S at 130°C for 2.3-3.0 h was 79.40, 85.93, 87.70, and 88.43%, respectively. WH treated with Na₂SO₃ showed higher hydrolysis yield (86.34%) as compared to Na₂S while other biomass substrates showed 2.0-3.0% less yield with Na₂SO₃. Resulting sugars were evaluated as substrate for lactic acid production, yielding 26.48, 25.36, 31.73, and 30.31 gL⁻¹ of lactic acid with 76.0, 76.0, 86.0, and 83.0% conversion yield from CC, BG, WH, and RH hydrolyzate, respectively.
Department of Chemistry, GC University, Katchery Road, Lahore 54000, Pakistan.
Muhammad
M
Idrees
Ahmad
A
Adnan
Fahim Ashraf
FA
Qureshi
D000704:Analysis of Variance; D018533:Biomass; D002384:Catalysis / Q000187:drug effects; D002855:Chromatography, Thin Layer; D031806:Eichhornia / Q000737:chemistry; D005285:Fermentation / Q000187:drug effects; D006868:Hydrolysis / Q000187:drug effects; D007700:Kinetics; D019344:Lactic Acid / Q000096:biosynthesis*; D007778:Lactobacillus / Q000187:drug effects / Q000378:metabolism; D008031:Lignin / Q000302:isolation & purification / Q000378:metabolism*; D012275:Oryza / Q000737:chemistry; D011134:Polysaccharides / Q000302:isolation & purification; D013440:Sulfides / Q000494:pharmacology*; D013447:Sulfites / Q000494:pharmacology*; D013696:Temperature; D013997:Time Factors
D011134:Polysaccharides; D013440:Sulfides; D013447:Sulfites; C036909:lignocellulose; D019344:Lactic Acid; C007916:hemicellulose; D008031:Lignin; C033479:sodium sulfide