No abstract

In the last few years, soil deterioration due to excessive application of synthetic agrochemical has become growing concern. Use of organic fertilizer is believed to be able to enhance soil quality. The objective of this experiment was to determine nitrogen, phosphorus, and potassium uptakes by sweet corn as affected by local based liquid organic fertilizer (LOF) under closed agriculture system. The experiment was conducted in Closed Agriculture Production System (CAPS) Research Station in Air Duku Village, Bengkulu, Indonesia from March to June 2015, employing Randomized Completely Block Design with 2 factors. The first factor was 3 sweet corn genotypes, i.e. Talenta, Jambore, and Asian Honey and the second factor was 5 rates of LOF, i.e. 0, 25, 50, 75, and 100 mg l-1 , respectively. Each treatment combination was replicated 3 times. Foliar application of LOF was carried out every week at 2-8 weeks after planting (WAP) with total volume of 600 ml per plant. Sweet corn leaves were sampled at the beginning of tassel emergence. The experiment revealed that sweet corn genotype significantly influenced the uptake of nitrogen, but not phosphorus and potassium. It was observed that Asian Honey genotype absorbed highest nitrogen as compared to other genotypes. In addition, increase in rates of LOF significantly raised nitrogen uptake by sweet corn, but not phosphorus and potassium.

Sample particle size is an important parameter in the solid–liquid extraction system of natural products for obtaining their bioactive compounds. This study evaluates the effect of sample particle size on the phytochemical composition and antioxidant activity of brown macroalgae Sargassum cristaefolium. The crude ethanol extract was extracted from dried powders of S.cristeafolium with various particle sizes (> 4000 µm, > 250 µm, > 125 µm, > 45 µm, and < 45 µm). The ethanolic extracts of S.cristaefolium were analysed for Total Phenolic Content (TPC), Total Flavonoid Content (TFC), phenolic compound concentration and antioxidant activities. The extract yield and phytochemical composition were more abundant in smaller particle sizes. Furthermore, the TPC (14.19 ± 2.08 mg GAE/g extract to 43.27 ± 2.56 mg GAE/g extract) and TFC (9.6 ± 1.8 mg QE/g extract to 70.27 ± 3.59 mg QE/g extract) values also significantly increased as particle sizes decreased. In addition, phenolic compounds epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), and Epigallocatechin gallate (EGCG) concentration were frequently increased in samples of smaller particle sizes based on two-way ANOVA and Tukey’s multiple comparison analysis. These results correlate with the significantly stronger antioxidant activity in samples with smaller particle sizes. The smallest particle size (< 45 µm) demonstrated the strongest antioxidant activity based on DPPH, ABTS, hydroxyl assay and FRAP. In addition, ramp function graph evaluates the desired particle size for maximum phytochemical composition and antioxidant activity is 44 µm. In conclusion, current results show the importance of particle size reduction of macroalgae samples to increase the effectivity of its biological activity.

Acidic and chemical inhibitor stresses undermine efficient lactic acid bioproduction from lignocellulosic feedstock. Requisite coping treatments, such as detoxification and neutralizing agent supplementation, can be eliminated if a strong microbial host is employed in the process. Here, we exploited an originally robust yeast, Saccharomyces cerevisiae BTCC3, as a production platform for lactic acid. This wild-type strain exhibited a rapid cell growth in the presence of various chemical inhibitors compared to laboratory and industrial strains, namely BY4741 and Ethanol-red. Pathway engineering was performed on the strain by introducing an exogenous LDH gene after disrupting the PDC1 and PDC5 genes. Facilitated by this engineered strain, high cell density cultivation could generate lactic acid with productivity at 4.80 and 3.68 g L−1 h−1 under semi-neutralized and non-neutralized conditions, respectively. Those values were relatively higher compared to other studies. Cultivation using real lignocellulosic hydrolysate was conducted to assess the performance of this engineered strain. Non-neutralized fermentation using non-detoxified hydrolysate from sugarcane bagasse as a medium could produce lactic acid at 1.69 g L−1 h−1, which was competitive to the results from other reports that still included detoxification and neutralization steps in their experiments. This strategy could make the overall lactic acid bioproduction process simpler, greener, and more cost-efficient.

Solid organic fertilization in organic farming practices should be supplemented with liquid organic fertilizer to accelerate the availability of plant nutrients. The study aimed to determine performance and major nutrient uptake by sweet corn following application of vermicompost supplemented with liquid organic fertilizer (LOF) and to find out combined vermicompost and liquid organic fertilizer for sweet corn production. The experiment was conducted at CAPS Research Station (1054 m above sea level) from April to June 2016, arranged in split plot design with 5 rates of vermicompost as the main plot and 5 rates of LOF as the subplot. Rates of vermicompost comprised 5, 10, 15, 20, and 25 Mg ha-1 , while LOF rates consisted of control, 25, 50, 75, and 100% (initial concentration). Treatment combination was replicated 3 times. Root application of LOF was carried out every week at 2-8 weeks after planting (WAP) with total volume of 950 ml plant-1. Result pointed out that vermicompost pronouncedly raised nitrogen (N), phosphorus (P) and potassium (K) uptakes and linearly enhanced growth and yield of sweet corn, indicated by plant height, plant leaf area, shoot fresh and dry weight, weight of husked and unhusked ears, diameter of ear, and weight of husked ear per plot but length of ear. The addition of LOF had a similar effect on major nutrient uptake, growth, and yield of sweet corn. Vermicompost at the rate of 25 Mg ha-1 supplemented with 100% LOF provided greatest growth and yield, suggesting that the fertilizer combination was the most effective complementary organic fertilization for sweet corn production in the organic farming system.