Abstract of Masters Thesis

(1)

BIOBUTANOL PRODUCTION FROM AGRO-INDUSTRIAL WASTES AS

SUBSTRATES USING Clostridium saccharoperbutylacetonicum N1-4 (ATCC13564)

NAJEEB KAID NASSER AL-SHORGANI

University Kebangsaan Malaysia (The National University of Malaysia)Master of Science in Microbiology

ABSTRACT

The aim of this study is to produce biobutanol by Clostridium saccharoperbutylacetonicum

N1-4 (ATCC 13564) from different renewable biomass. The environmental parameters for acetone-butanol-ethanol (ABE) production of palm oil mill effluent (POME) by C.

saccharoperbutylacetonicum N1-4 were investigated. Various pretreatment procedures

including acidic, alkaline, enzymatic and combination between acidic and enzymatic methods were applied on POME, rice bran (RB) and de-oiled rice bran (DRB) in order to generate more fermentable sugars. This study also investigated the effect of butyric acid addition to the culture of C. saccharoperbutylacetonicum N1-4 on butanol production. The results show that the best conditions for ABE and butanol production from POME were; sedimented POME, 15% inoculum size, 5.8 pH, 30 ⁰C incubation temperature, zero agitation speed, and in the absence of crude palm oil. Among the pretreatment methods, enzymatic hydrolysis was the most suitable for ABE production from POME which produced the highest ABE productivity of 0.06 g/L.h and 0.043 g/L.h of biobutanol. Further treatment of POME hydrolysate with XAD-4 resin improved ABE production to 4.29 g/L with a yield of 0.29 g/g. For biobutanol, the production improved to 3.09 g/L. Dilute acid pretreatment for RB and DRB produced comparable reducing sugars to enzymatic hydrolysis. Combined hydrolysis of 10% RB resulted in total ABE production of 8.88 g/L with a yield of 0.28 g/g and a productivity of 0.07 g/L.h whereas, the total ABE, yield and productivity obtained from combined hydrolysis of 10% DRB were, 10.51 g/L, 0.40 g/g and 0.088 g/L.h, respectively.

When RB and DRB hydrolysates were treated with XAD-4 resin, the production of ABE

increased to 9.92 and 12.13 g/L, respectively, and ABE yields were also increased to 0.35 and 0.44 g/g respectively. Direct fermentation of 7% sago starch produced 16.65 g/L ABE in which 9.83 g/L is butanol with an ABE productivity of 0.15 g/L.h when supplemented with P2 medium while, only 13.33 g/L ABE was produced when supplemented with TYA medium with an ABE productivity of 0.11 g/L.h. The use of sago starch resulted in the highest concentrations of ABE and biobutanol. The study showed that the addition of 4 g/L butyric acid resulted in the best concentration and 23.51 g/L total ABE was produced containing 17.71 g/L butanol with an ABE productivity of 0.2 g/L.h when TYA medium was used. C. saccharoperbutylacetonicum N1-4 was also detected to produce butanol in a limited nutrient medium containing glucose and butyric acid. Combination of 10 g/L of butyric acid and 20 g/L of glucose was found to produce 13 g/L of butanol which indicates the importance of the glucose to butyric acid ratio for the enhancement of butanol production. Agro-industrial wastes such as palm oil mill effluent (POME), sago starch, rice bran (RB) and de-oiled rice bran (DRB) have potential value to be used as feedstock for renewable energy production such as biobutanol. 

(2)

Bacteriological Studies on Sludge from Some Municipal Wastewater Treatment Plants in Republic of Yemen

Adel A. S. Al-Gheethi

Abstract of Master Thesis

ABSTRACT

The study conducted to evaluate the capabilities of wastewater treatment plants in reducing the densities of faecal indicators and pathogens in sludge from four wastewater treatment plants at republic of Yemen. Total coliforms (TC), faecal coliforms (FC), Fecal streptococci, Salmonella spp. and Shigella sp.as well as heavy metals copper (Cu²⁺), nickel (Ni²⁺)and zinc (Zn²⁺) were investigated. The results showed that the density of FC was higher than the guideline limit recommended by United State Environmental Protection Agency (U.S. EPA) Class A(<1000 cell/ 100 ml) and Salmonella spp. (<4 cell/25 g). These results suggest a further treatments for the sludge to reduce the density of pathogenic bacteria to meet standards limits of sludge disposal or reuse. Therefore, the effectiveness of storage period, heat treatment (60 and 80^oC) and lime stabilization in reduction of faecal indicators and elimination of pathogenic bacteria were evaluated. The sludge complies with U. S. EPA standards after 6 months of the storage period at 25±2^oC. Heat treatment reduced FC to meet the U.S. EPA standards after 1h at 80°C. Alkaline treatment by lime stabilization could reduce FC density to meet the requirements of U.S. EPA standards for Class A criteria after 24 h and Salmonellaspp. after 120 h. Among 127 bacterial isolates; five bacterial strains identified as Bacillus pasteurii 586S, B. megaterium 1295S, B.subtilis 117S, Pseudomonas cepacia 120S and Staphylococcus xylosus 222W were selected for removal of Ni²⁺ ions and study of biosorption process. Results found that Gram-positive bacteria had more efficiencyin removal of nickel ions than Gram-negative bacteria; dead cell biomass had more biosorption efficiency than living cells biomass. Carboxyl group, amino group and phosphate group play important role in biosorption process. B. megaterium 1295S was selected as most potent cellulase producer among the bacterial species studied. The optimization of CMCase production was 0.4 ml of the bacterial suspension, at 45°C and pH 6.5 for 72 h with citrate phosphate buffer and phosphate buffers. The best cellulosic material for the highest CMCase production was CMC, while mannose was the best carbon source,sludge media induce the CMCase production by B. megaterium 1295S. Among 21 amino acids used as nitrogen source L-hydroxy prolinewas the best nitrogen source for production of CMCase enzyme.