Pengaruh Segmentasi Pasar Terhadap Peningkatan Volume Penjualan

Penelitian ini untuk mengetahui besar pengaruh segmentasi pasar terhadap peningkatan volume penjualan. Jenis penelitian ini adalah penelitian kuantitatif. Populasi dalam penelitian ini adalah konsumen Yongky Mart Kota Gunungsitoli yang berjumlah 30 orang. Jenis data yang digunakan dalam penelitian ini adalah data primer. Teknik pengumpulan data dengan observasi, kuesioner. Hasil Segmentasi pasar berpengaruh terhadap peningkatan volume penjualan di Yongky Mart Kota Gunungsitoli sebesar 58,982% sedangkan sisanya dipengaruhi oleh faktor-faktor lain yang tidak termasuk dalam variabel penelitian ini sebesar 41,018%. Sehingga segmentasi pasar mampu mempengaruhi peningkatan volume penjualan di Yongky Mart Kota Gunungsitoli.

Production and Regulation of Pectinases from Indigenously Isolated Yeast Strains

Pectinases are industrially important carbohydrases that are generally obtained on large scale by filamentous fungi. Although, yeasts have a great potential to produce several industrial enzymes, however, they have been evaluated less frequently for the production of pectinases. This gap envisaged the current study to isolate and assess the potential of indigenous yeast strains for the production of pectinase. Thirty two (32) yeasts strains were isolated from various sources out of which 13 strains isolated from soil samples, 9 from dairy products, 4 from mayonnaise and 6 were isolated from rotten fruits and vegetables. All the strains were purified on SDA and majority of them appeared as ovalshaped in microscopy while some of them had brick shape. In addition to this, ninety five (95) yeast strains were included in screening process from the pool of cultures isolated by other colleagues. Total one hundred and twenty seven (127) strains were screened on mineral salt medium (MSM) agar plates for pectinase production using ruthenium red dye. Out of 127, forty eight (48) strains were found pectinolytic and were selected for further screening by submerged fermentation. Eleven (11) strains from these 48 strains produced significant titers (≥ 0.15 IU/ml) of pectinases. Four strains namely AA1, AA9, AA14 and AA15 producing > 0.250 IU/ml of pectinase were selected for further studies. The effects of various factors affecting the pectinase production from these selected strains were evaluated by Plackett-Burman design (PBD). Seven factors namely temperature, initial pH, inoculum size, incubation period, glucose concentration, substrate concentration and media were studied for their significance. None of the factors was found significant for the strains AA1, AA9 and AA14 whereas three factors including inoculum size, initial pH and substrate concentration were appeared as significant for pectinase production from the strain AA15 and optimized further by Box-Behnken design (BBD) as an Response surface methodology (RSM) approach. This promising strain was identified as Geotrichum candidum AA15 on the basis of microscopic, cultural, biochemical and 18S rDNA sequence analysis The strain produced highest titers of pectinase (0.250 IU/ml) when fermentation was carried out in MSM media with pH 5.3 xxv using 0.75% citrus pectin at 25ºC for 48 h and inoculated with 3% of inoculum. The results of growth and enzyme production kinetics showed that maximum pectinase production was associated with growth and obtained during late exponential or early stationary phase. Furthermore, some studies were conducted on the regulation of enzyme production from AA15. The results revealed that the strain AA15 produced enzyme constitutively but the incorporation of galacturonic acid in pectin containing media at any stage of fermentation resulted in complete inhibition of pectinase production indicating some self-catabolic repression. Afterwards, crude pectinase from the strain AA15 was characterized and parameters influencing catalytic activity were studied. The data showed that reaction at 35ºC for 25 min in an acidic environment of pH 5 best suits the enzyme activity. The enzymatic activity was not drastically affected when temperature varied. Indeed it retained 100% activity at 30 ºC until 1 h. Whereas, Tm was calculated as 42 ºC. It also exhibited high stability at pH 2-3. Presence of higher amount of substrate (citrus pectin) i.e. 2.5% was found optimum. The kinetic parameters for affinity of the enzyme, Km was calculated as 24.69 mg/ml and for rate of reaction, Vmax as 0.91 µmole/min. Studies were also carried out to determine the effect of various chemicals on pectinolytic activity. Zn2+, Fe2+, NH4+ and urea were found as activators for pectinase activity while the presence of Co2+, Mg2+ and EDTA in reaction mixture reduced the pectinase activity. Among the surfactants studied, SDS caused the complete loss of pectinase activity whereas tween-80 and tritonX-100 inhibited or slightly enhanced the pectinase activity, respectively. Two isoforms of pectinase with molecular weight of 60 and 66.2 KDa were detected by SDS PAGE and zymography. The crude pectinase was also applied for clarification of orange juice. A Box-Behnken design was executed for the optimization of enzymatic treatment of orange juice. The optimum clarity of 61% was obtained when juice was treated with 4% (v/v) of pectinase at 30ºC for 180 min. These results were promising for the use of this enzyme for fruit juice clarification. xxvi Co-culturing of AA15 with two other yeast strains was performed for the production of pectinase using sugarcane bagasse as a substrate. An enhancement in the pectinase production was observed with consortium as compared to mono-culture suggesting that the hydrolysis of cellulose and hemicellulose contents by the other strains made the pectic portion available for the strain AA15. Moreover, gravimetric analysis and SEM of substrate fermented by co-culture also revealed more degradation in the substrate than mono-culture. This study demonstrates that the indigenous pectinolytic yeast could be a potential candidature for future biotechnological applications.