Starch extracted from pineapple (Ananas comosus) plant stem as a source for amino acids production

Background Pineapple plant (Ananas comosus) is one of the largest productions in Asia and its increasing production has generated a huge amount of pineapple wastes. Pineapple plant stem is made up of high concentration of starch which can potentially be converted into value-added products, including amino acids. Due to the increasing demand in animal feed grade amino acids, especially for methionine and lysine, the utilisation of cheap and renewable source is deemed to be an essential approach. This study aimed to produce amino acids from pineapple plant stem hydrolysates through microbial fermentation by Pediococcus acidilactici Kp10. Dextrozyme was used for hydrolysis of starch and Celluclast 1.5 L for saccharification of cellulosic materials in pineapple plant stem. Results The hydrolysates obtained were used in the fermentation to produce methionine and lysine. Pineapple plant stem showed high starch content of 77.78%. Lignocellulosic composition of pineapple plant stem consisted of 46.15% hemicellulose, 31.86% cellulose, and 18.60% lignin. Saccharification of alkaline-treated pineapple plant stem gave lower reducing sugars of 13.28 g/L as compared to untreated, where 18.56 g/L reducing sugars obtained. Therefore, the untreated pineapple plant stem was selected for further process. Starch hydrolysis produced 57.57 g/L reducing sugar (100% hydrolysis yield) and saccharification of cellulosic materials produced 24.67 g/L reducing sugars (56.93% hydrolysis yield). The starch-based and cellulosic-based of pineapple plant stem were subjected as carbon source in methionine and lysine production by P. acidilactici Kp10. Conclusions In conclusion, higher methionine and lysine production were produced from starch-based hydrolysis (40.25 mg/L and 0.97 g/L, respectively) as compared to cellulosic-based saccharification (37.31 mg/L and 0.84 g/L, respectively) of pineapple plant stem. Graphical Abstract

Chemical Pretreatment And Enzymatic Hydrolysis Of Mixed Source-Separated Organic (SSO) And Wood Waste

This paper examines the effectiveness of two pretreatments on Source-Separated Organic waste (SSO) mixed with wood wastes: long term lime for SSO mixed with forestry waste (hardwoods), and the cellulose solvent-organic lignocellulose fractionation (COSLIF) method, with SSO and demolition waste (softwoods). For long term lime treatment, the highest overall conversions from cellulose to glucose and xylose were 50.4%, and 43.5% respectively. The best temperature found for long term lime pretreatment was 65°C. The COSLIF pretreatment glucose yield was found to be 93.7%. The highest enzyme hydrolysis yield found was 93.5% for a cellulase loading of 30 FPU/g glucan at 50°C. The best hydrolysis yield found at lower loading (10 FPT/g glucan), was 83.5%. At 40 and 50°C, all peak hydrolysis yields were achieved between 12 and 24 hours. A drop in temperature below 40°C caused a slowing of the hydrolysis rate.

Chemical Pretreatment And Enzymatic Hydrolysis Of Mixed Source-Separated Organic (SSO) And Wood Waste

This paper examines the effectiveness of two pretreatments on Source-Separated Organic waste (SSO) mixed with wood wastes: long term lime for SSO mixed with forestry waste (hardwoods), and the cellulose solvent-organic lignocellulose fractionation (COSLIF) method, with SSO and demolition waste (softwoods). For long term lime treatment, the highest overall conversions from cellulose to glucose and xylose were 50.4%, and 43.5% respectively. The best temperature found for long term lime pretreatment was 65°C. The COSLIF pretreatment glucose yield was found to be 93.7%. The highest enzyme hydrolysis yield found was 93.5% for a cellulase loading of 30 FPU/g glucan at 50°C. The best hydrolysis yield found at lower loading (10 FPT/g glucan), was 83.5%. At 40 and 50°C, all peak hydrolysis yields were achieved between 12 and 24 hours. A drop in temperature below 40°C caused a slowing of the hydrolysis rate.

Effect of Intermediate Washing on Ozonolysis Delignification and Enzymatic Hydrolysis of Wheat Straw

Wheat straw was pretreated with ozone to increase the enzymatic hydrolysis yield. Ozonolysis pretreatment was performed in two stages with an intermediate washing step with water in between. Part of the delignification products (lignin fragments) were removed by a washing step so ozone was used to oxidize more lignin rather than oxidizing lignin fragments. Three parameters, i.e. Initial Water Content (IWC) in wheat straw, Washing Starting Time (WST), and Washing Contact Time (WCT), were optimized to minimize Acid Insoluble Lignin (AIL) content of ozonated wheat straw. Performing an experiment using optimal parameters' values, i.e. IWC equal to 45 wt. %, WST equal to 20 minutes and WCT equal to 80 seconds, showed a drop in AIL content to 9.35 % with an increase in enzymatic hydrolysis yield to 80 % of the theoretical. Readjusting water content of wheat straw to 45 % before performing the 2nd ozonolysis stage further reduced AIL content to 7.36 % and increased the hydrolysis yield to 90 %. Increasing wheat straw fiber size from < 2 mm to < 6 mm decreased the hydrolysis yield to 72 %. All results were considered significant improvements when compared to untreated wheat straw with AIL content of 20.5 % and hydrolysis yield of 23 %.

Effect of Intermediate Washing on Ozonolysis Delignification and Enzymatic Hydrolysis of Wheat Straw

Wheat straw was pretreated with ozone to increase the enzymatic hydrolysis yield. Ozonolysis pretreatment was performed in two stages with an intermediate washing step with water in between. Part of the delignification products (lignin fragments) were removed by a washing step so ozone was used to oxidize more lignin rather than oxidizing lignin fragments. Three parameters, i.e. Initial Water Content (IWC) in wheat straw, Washing Starting Time (WST), and Washing Contact Time (WCT), were optimized to minimize Acid Insoluble Lignin (AIL) content of ozonated wheat straw. Performing an experiment using optimal parameters' values, i.e. IWC equal to 45 wt. %, WST equal to 20 minutes and WCT equal to 80 seconds, showed a drop in AIL content to 9.35 % with an increase in enzymatic hydrolysis yield to 80 % of the theoretical. Readjusting water content of wheat straw to 45 % before performing the 2nd ozonolysis stage further reduced AIL content to 7.36 % and increased the hydrolysis yield to 90 %. Increasing wheat straw fiber size from < 2 mm to < 6 mm decreased the hydrolysis yield to 72 %. All results were considered significant improvements when compared to untreated wheat straw with AIL content of 20.5 % and hydrolysis yield of 23 %.

Production Of Bioplastics From Renewable And Sustainable Feedstock Resources

This study illustrates the potential opportunity for the utilization of hemp to produce PHB (poly(3-hydroxybutyrate). The objective of the study was to optimize simple sugar availability from hemp for Ralstonia eutropha. The use of three pre-treatment methods (grinded – 5% NaOH – Autoclave at 121 oC for 60 minutes) was able to provide a better fractional insoluble solids (FIS) of ≃ 61 % that was significantly better compared to other combinations of pre-treatments studied. Optimum enzyme dosage was also determined by comparing different enzyme concentrations and found that three enzymes should contain a dose of 1.5 g /L. The optimum pretreatment and hydrolysis conditions resulted in a better enzyme hydrolysis yield of 10.9 % and PHB yield of ≃ 43 %. Results also demonstrate that sonification did not improve PHB recovery, while pH control increased PHB recovery. Keywords: Hemp, Ralstonia eutropha, PHB, Pre-treatment, Enzyme Hydrolysis

Production Of Bioplastics From Renewable And Sustainable Feedstock Resources

This study illustrates the potential opportunity for the utilization of hemp to produce PHB (poly(3-hydroxybutyrate). The objective of the study was to optimize simple sugar availability from hemp for Ralstonia eutropha. The use of three pre-treatment methods (grinded – 5% NaOH – Autoclave at 121 oC for 60 minutes) was able to provide a better fractional insoluble solids (FIS) of ≃ 61 % that was significantly better compared to other combinations of pre-treatments studied. Optimum enzyme dosage was also determined by comparing different enzyme concentrations and found that three enzymes should contain a dose of 1.5 g /L. The optimum pretreatment and hydrolysis conditions resulted in a better enzyme hydrolysis yield of 10.9 % and PHB yield of ≃ 43 %. Results also demonstrate that sonification did not improve PHB recovery, while pH control increased PHB recovery. Keywords: Hemp, Ralstonia eutropha, PHB, Pre-treatment, Enzyme Hydrolysis

Co-production of Xylooligosaccharides and Xylose From Poplar Sawdust by Recombinant Endo-1,4-β-Xylanase and β-Xylosidase Mixture Hydrolysis

As is well-known, endo-1,4-β-xylanase and β-xylosidase are the rate-limiting enzymes in the degradation of xylan (the major hemicellulosic component), main functions of which are cleavaging xylan to release xylooligosaccharides (XOS) and xylose that these two compounds have important application value in fuel, food, and other industries. This study focuses on enzymatic hydrolysis of poplar sawdust xylan for production of XOS and xylose by a GH11 endo-1,4-β-xylanase MxynB-8 and a GH39 β-xylosidase Xln-DT. MxynB-8 showed excellent ability to hydrolyze hemicellulose of broadleaf plants, such as poplar. Under optimized conditions (50°C, pH 6.0, dosage of 500 U/g, substrate concentration of 2 mg/mL), the final XOS yield was 85.5%, and the content of XOS2−3 reached 93.9% after 18 h. The enzymatic efficiency by MxynB-8 based on the poplar sawdust xylan in the raw material was 30.5%. Xln-DT showed excellent xylose/glucose/arabinose tolerance, which is applied as a candidate to apply in degradation of hemicellulose. In addition, the process and enzymatic mode of poplar sawdust xylan with MxynB-8 and Xln-DT were investigated. The results showed that the enzymatic hydrolysis yield of poplar sawdust xylan was improved by adding Xln-DT, and a xylose-rich hydrolysate could be obtained at high purity, with the xylose yield of 89.9%. The enzymatic hydrolysis yield was higher (32.2%) by using MxynB-8 and Xln-DT together. This study provides a deep understanding of double-enzyme synergetic enzymolysis of wood polysaccharides to valuable products.

Organosolv lignin properties and their effects on enzymatic hydrolysis

Lignin plays a crucial role in enzymatic hydrolysis of lignocellulosic biomass. To evaluate the correlation between lignin properties and its effects on enzymatic hydrolysis, five organosolv lignins (OLs) were isolated from woody biomass, and their physico-chemical properties and structural features were characterized. The effects of OL addition on enzymatic hydrolysis of microcrystalline cellulose (pure cellulose) were assessed first, which showed their disparate effects. The addition of three OLs increased the 72 h hydrolysis yield by 7.4% to 10.1%, while the addition of other two OLs reduced the 72 h hydrolysis yield by 3.2% to 20.4%. A strong correlation between the enzyme distribution coefficient on lignins and the 72 h hydrolysis yields indicated that the enzyme-lignin interaction played a significant role in determining the lignin effects. More importantly, a correlation between lignin properties (hydrophobicity, zeta potential, and particle size) and the enzyme distribution coefficient was established. Identifying the key lignin properties will give insights to reduce the lignin inhibition by altering the lignin properties, thereby promoting enzymatic hydrolysis of lignocellulose.