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This study evaluated the production of marine biodegradable plastics, specifically polyhydroxyalkanoates (PHAs), using waste paper from food containers as a novel material source. The results showed that adding dilute sulfuric acid as a pretreatment may have a negative impact on enzyme hydrolysis efficiency. Without pretreatment, the highest glucose concentration was observed in the 50-min heating group. In the experimental group with 1% dilute sulfuric acid as a pretreatment, the highest average glucose concentration was observed in the 25-min treatment group. In flask scale experiments, the C/N ratio was controlled at 10, 20, and 30. The results showed that when the C/N ratio was 10, the PHA/CDM ratios were 16.3 and 23.6 at 48 and 72 h, respectively. After 96 h of cultivation using hydrolysis liquid from the waste paper container as the sole carbon source in a 5-L scale experiment, the PHA/CDM ratio was 28.7 and the PHA concentration was 0.95 g/L. The potential bacterial strain in this study was confirmed to be a Bacillus genus bacterium after strain identification. The signal peaks indicated that the PHA obtained from the Bacillus sp. production process was PHB. [ABSTRACT FROM AUTHOR]

Because of their lower environmental impact, biodegradable polymers such as polyhydroxyalkanoates (PHAs) produced within cultured bacteria represent promising alternatives to petroleum-based plastics. PHA production in flasks yielded optimal results with a carbon-to-nitrogen ratio of 22. The 5-L scale experimental results revealed that when glucose was used as the carbon source, Cupriavidus necator could produce 4.74 g/L PHA with 77.6% of PHA content in the microorganism 72 h after the initiation of the experiment. When the hydrolysis liquid from inedible rice was used as the carbon source, the highest concentration of PHA and ratio of PHA content in the microorganism were 4.82 g/L and 68.6%, respectively, after 72 h. Using the hydrolysis liquid from inedible rice as the carbon source reduced the culture cost and shortened the culture time, without affecting the structure of the PHA during production. Using the hydrolysis liquid from rice as the carbon source in PHA production (by C. necator) yielded optimal results, and the results may serve as a reference for applications involving other PHA-producing bacteria. Employing alternative carbon sources to culture bacteria might become a means of increasing the productivity and ensuring the quality of PHA products in the future. [ABSTRACT FROM AUTHOR]

Lignocellulosic ethanol production at high temperature offers advantages such as the decrease of contamination risk and cooling cost. Recombinant xylose-fermenting Saccharomyces cerevisiae has been considered a promising strain for ethanol production from lignocellulose for its high inhibitor tolerance and superior capability to ferment glucose and xylose into ethanol. To improve the ethanolic fermentation by xylose at high temperature, the strain YY5A was subjected to the ethyl methanesulfonate (EMS) mutagenesis. A mutant strain T5 was selected from the EMS-treated cultures to produce ethanol. However, the xylose uptake by T5 was severely inhibited by the high ethanol concentration during the cofermentation in defined YPDX medium at 40 °C. In this study, the simultaneous saccharification and co-fermentation (SSCF) and the separate hydrolysis and co-fermentation (SHCF) processes of sugarcane bagasse were assessed to solve this problem. The xylose utilization by T5 was remarkably improved using the SSCF process compared to the SHCF process. For the SHCF and SSCF processes, 48% and 99% of the xylose in the hydrolysate was consumed at 40 °C, respectively. The ethanol yield was enhanced by the SSCF process. The ethanol production can reach to 36.0 g/L using this process under high-temperature conditions. [ABSTRACT FROM AUTHOR]

Due to environmental concerns and the proposed global policies for reducing carbon emissions, lignocellulosic biomass is an attractive renewable feedstock for biofuel and biochemical production. Wood residues from the plywood industry have a lignin content as high as 30.7% ± 0.1%. Diluted acid pretreatment followed by enzymatic hydrolysis is often employed to release sugar from lignocellulosic biomass. A high lignin content limits the accessibility of cellulose. Lignin also binds with enzymes, which reduces the enzymatic hydrolysis efficiency. In this study, different concentrations of polyethylene glycol (PEG) 6000 were used as an additive to inhibit the detrimental effects caused by lignin. The optimal dosage was 1 g/L, which increased the glucose production to 35.8% and 26.6% for solid-to-liquid ratios of 2% and 20%, respectively. The results suggest that PEG 6000 is a suitable potential additive for increasing the bioethanol production from plywood residue in upscale operations. [ABSTRACT FROM AUTHOR]

The isolated bacterium Lactobacillus plantarum is strongly tolerant of lignocellulose-derived inhibitory compounds and possesses the ability to produce lactic acid in the presence of 8.0 g/L furfural, 6.0 g/L hydroxymethylfurfural, 4.0 g/L vanillin, and 4.0 g/L syringaldehyde. This bacterium was used in an integrated simultaneous saccharification and fermentation (SSF) process for the production of lactic acid using whole rice straw slurry (with a high solids content of 17%) that had been pretreated with dilute sulfuric acid. This method achieved a lactic acid concentration of 65.6 g/L, which corresponded to a cellulose-to-lactic acid conversion yield of 69%. These results demonstrated that isolated bacterium and the proposed integrated SSF process are able to produce high concentrations of lactic acid. Furthermore, this proposed process does not require detoxification and had a conversion efficiency that is comparable to that obtained using the conventional SSF process, which requires the addition of fresh water. Therefore, it was concluded that the proposed process is promising for commercial lactic acid production and could make the production of lactic acid from lignocellulosic biomass more practical in the future. [ABSTRACT FROM AUTHOR]