Study on characteristics of acacia wood by FTIR and thermogrametric analysis

Renewable energy is very important for future development of society. Biomass is a type of energy that can be renewable. In this study, characterization of acacia wood is focused and discussed. The functional groups, crosslinking in the biomass structures and thermal decomposition were mentioned. In that, functional groups, crosslinking of acacia wood are analyzed by Fourier transform infrared spectroscopy and thermal decomposition is investigated with thermogravimetric equipment. Acacia wood has typical group of wood from FT-IR such as O-H, C-H, C-O, C-O-C of cellulose and lignin. The structure of cellulose is also very easy to be broken by thermal factor. In the inert atmosphere, cellulose decomposed dramatically in the temperature range of 280 to 550 °C and degradation of lignin occurred in the temperature range of 100 to 800 °C. Acacia wood decomposed in the temperature range of 200 to 580 °C with three distinct weight loss stages. The first stage is water removal of biomass and it completes below 120 oC. The second stage is in the range of 200-350 oC that is the initial decomposition of biomass and directly related to the formation of volatile substances from decomposition of hemicellulose and cellulose. The last stage is the continuous decomposition of lignin at higher temperature up to 580 oC. For cellulose, the thermal degradation in air atmosphere has decomposition temperature higher than that in the nitrogen atmosphere but the ending temperature is lower. On the other hand, the thermal decomposition of lignin just occurred from 150 to 560 oC. The reaction for acacia wood demonstrated three stages. The water evaporated at lower than 120 oC in the first stage. The second stage is the devolatilization of biomass (214-322 oC) and the third one (322-420 oC) is the combustion of char. Keywords. Biomass, acacia wood, cellulose and lignin, FT-IR, characterization of biomass

Molecular cloning gene and nucleotide sequence of the gene encoding an endo-1,4-β-glucanase from Bacillus sp VLSH08 strain applying to biomass hydrolysis: Research article

Bacillus sp VLSH08 screened from sea wetland in Nam Dinh province produces an extracellular endo-1,4-beta-glucanase. According to the results of the classified Kit API 50/CHB as well as sequence of 1500 bp fragment coding for 16S rRNA gene of the Bacillus sp VLSH 08 strain showed that the taxonomical characteristics between the strain VLSH 08 and Bacillus amyloliquefaciene JN999857 are similar of 98%. Culture supernatant of this strain showed optimal cellulase activity at pH 5.8 and 60 Celsius degree and that was enhanced 2.03 times in the presence of 5 mM Co2+. Moreover, the gene encoding endo-1,4-beta-glucanase from this strain was cloned in Escherichia coli using pCR2.1 vector. The entire gene for the enzyme contained a 1500-bp single open reading frame encoding 500 amino acids, including a 29-amino acid signal peptide. The amino acid sequence of this enzyme is very close to that of an EG of Bacillus subtilis (EU022560.1) and an EG of Bacillus amyloliquefaciene (EU022559.1) which all belong to the cellulase family E2. A cocktail of enzyme containing this endo-1,4-beta-glucanase used for biomass hydrolysis indicated that the cellulose conversion attained to 72.76% cellulose after 48 hours.Chủng vi khuẩn Bacillus sp VLSH08 được tuyển chọn từ tập hợp chủng vi khuẩn phân lập ở vùng ngập mặn tỉnh Nam Định có khả năng sinh tổng hợp enzyme endo-1,4-beta-glucanase ngoại bào. Kết quả phân loại chủng vi khuẩn Bacillus sp VLSH08 bằng Kit hóa sinh API 50/CHB cũng như trình tự gen mã hóa 16S rRNA cho thấy độ tương đồng của chủng Bacillus sp VLSH08 và chủng Bacillus amyloliquefaciene JN999857 đạt 98%. Dịch lên men của chủng được sử dụng làm nguồn enzyme thô để nghiên cứu hoạt độ tối ưu của enzyme ở pH 5,8 và nhiệt đô 60oC. Hoạt tính enzyme tăng 2,03 lần khi có mặt 5 mM ion Co2+. Đồng thời, gen mã hóa cho enzyme endo-1,4-betaglucanase cũng được tách dòng trong tế bào Escherichia coli sử dụng vector pCR 2.1. Gen mã hóa cho enzyme này có chiều dài 1500 bp, mã hóa cho 500 axit amin, bao gồm 29 axit amin của chuỗi peptid tín hiệu. So sánh cho thấy trình tự gen endo-1,4-beta-glucanase của chủng Bacillus sp VLSH08 có độ tương đồng cao với enzyme này của chủng Bacillus subtilis (EU022560.1) và của chủng Bacillus amyloliquefaciene (EU022559.1). Tất cả các enzyme nhóm này đều thuộc họ cellulase E2. Enzyme của chủng này cũng đã được phối trộn với các enzyme khác tạo thành cocktail để thủy phân sinh khối cho kết quả cellulose bị thủy phân 72,76% sau 48 giờ

On some multiplicity and mixed multiplicity formulas (Forum Math. 26(2014), 413-442)

This paper gives the additivity and reduction formulas for mixed multiplicities of multi-graded modules $M$ and mixed multiplicities of arbitrary ideals, and establishes the recursion formulas for the sum of all the mixed multiplicities of $M.$ As an application of these formulas we get the recursion formulas for the multiplicity of multi-graded Rees modules