Cassava starch-chitosan-sorghum micro-fibrillated cellulose biocomposite wrapping film to prevent COVID-19 outspread

To prevent virus spreading, the corpse or the coffin of COVID-19 patients need to be wrapped in plastic. Low-density polyethylene (LDPE), a crude oil-based wrapping plastic, is difficult to decompose in nature after use. In this study, biocomposite wrapping film was developed from cassava starch and chitosan, with the addition of sorghum Micro-Fibrillated Cellulose (MFC) by levels of 1%, 2%, 3%, 4% and 5%. Cassava starch (raw starch) was modified by acetic anhydride to produce acetylated cassava starch (acetylated starch) which is less hydrophilic thus enhance the compounding ability with LDPE. The sorghum MFC was obtained from sorghum fibers after following processes: soda pulping, bleaching and fibrillation with a super grinder. The addition of 1% sorghum MFC into raw starch-chitosan increased the tensile strength and modulus of elasticity by 33% and 17%, respectively. On the other hand, the addition of 2% sorghum MFC into acetylated starch-chitosan increased the elongation by 38%. Wrapping film needs to have good elongation ability so that it can be stretched during application. Based on elongation characteristic, acetylated cassava starch-chitosan with addition of 2% sorghum MFC can be developed to be a candidate for biocomposite wrapping film to prevent COVID-19 outspread.

Single-step ethanol production from raw cassava starch using a combination of raw starch hydrolysis and fermentation, scale-up from 5-L laboratory and 200-L pilot plant to 3000-L industrial fermenters

Background A single-step ethanol production is the combination of raw cassava starch hydrolysis and fermentation. For the development of raw starch consolidated bioprocessing technologies, this research was to investigate the optimum conditions and technical procedures for the production of ethanol from raw cassava starch in a single step. It successfully resulted in high yields and productivities of all the experiments from the laboratory, the pilot, through the industrial scales. Yields of ethanol concentration are comparable with those in the commercial industries that use molasses and hydrolyzed starch as the raw materials. Results Before single-step ethanol production, studies of raw cassava starch hydrolysis by a granular starch hydrolyzing enzyme, StargenTM002, were carefully conducted. It successfully converted 80.19% (w/v) of raw cassava starch to glucose at a concentration of 176.41 g/L with a productivity at 2.45 g/L/h when it was pretreated at 60 °C for 1 h with 0.10% (v/w dry starch basis) of Distillase ASP before hydrolysis. The single-step ethanol production at 34 °C in a 5-L fermenter showed that Saccharomyces cerevisiae (Fali, active dry yeast) produced the maximum ethanol concentration, pmax at 81.86 g/L (10.37% v/v) with a yield coefficient, Yp/s of 0.43 g/g, a productivity or production rate, rp at 1.14 g/L/h and an efficiency, Ef of 75.29%. Scale-up experiments of the single-step ethanol production using this method, from the 5-L fermenter to the 200-L fermenter and further to the 3000-L industrial fermenter were successfully achieved with essentially good results. The values of pmax,Yp/s, rp, and Ef of the 200-L scale were at 80.85 g/L (10.25% v/v), 0.42 g/g, 1.12 g/L/h and 74.40%, respectively, and those of the 3000-L scale were at 70.74 g/L (8.97% v/v), 0.38 g/g, 0.98 g/L/h and 67.56%, respectively. Because of using raw starch, major by-products, i.e., glycerol, lactic acid, and acetic acid of all three scales were very low, in ranges of 0.940–1.140, 0.046–0.052, 0.000–0.059 (% w/v), respectively, where are less than those values in the industries. Conclusion The single-step ethanol production using the combination of raw cassava starch hydrolysis and fermentation of three fermentation scales in this study is practicable and feasible for the scale-up of industrial production of ethanol from raw starch.

Hydroxypropylation Reduces Gelatinization Temperature of Corn Starch for Textile Sizing

A series of hydroxypropylated starch (HPS) that can be dissolved in water at 60-65℃ was obtained via two-step method in water system from corn starch. The structure and property of the HPS and its gelatinization temperature were characterized by Fourier transform infrared spectrometer (FTIR), nuclear magnetic resonance spectroscopy ( 1 H NMR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and transmission electron microscope (TEM). It was concluded that hydroxypropyl mainly bonded on the hydroxyl group at C 2 position from anhydroglucose unit of starch in the form of C-O-C, and the substitution level at C 6 position was slightly higher than that at C 3 position; and the crystallinity of starch decreased from 52.41% to 29.4% due to the introduction of hydroxypropyl and was confirmed by XRD. At the same time, the grooves on the surface of starch granules were observed by SEM. The above-mentioned two synergism promoted the permeation and transmission of water molecules in the starch microstructure. Moreover, the gelatinization temperatures and enthalpy of synthetic HPS was lower than that of raw corn starch, as further confirmed by DSC. This caused the HPS with a molar substitution greater than 0.1 soluble in water at 65℃, and the dissolution state was similar to that of at 95℃ (transmittance above 55%), as well as exhibited high slurry stability. Interestingly, compared with the raw starch, the HPS film showed excellent mechanical property at the relative humidity of 65%, which could be attributed to the hydrophilic ether bond and the flexible alkyl chain bonded on the structure of starch. This study will provide a new way for the preparation of high performance starch size for sizing yarn at medium low temperature.