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A study was conducted to investigate the effects of different food concentrations consisting of Nannochloropsis oculata (4 × 102, 4 × 104, 4 × 106 cells ml− 1 and control) on male and ephippia production in a tropical cladoceran, Moina micrura. The highest number of males (186.7 ± 13.4 males l− 1) was produced in cultures fed with 4 × 102 cells ml− 1 of N. oculata (FC 3) when the population density reached > 1600 individuals l− 1. Similarly, the highest total mean number of ephippia (160.0 ± 0.0 ephippia l− 1) was achieved in M. micrura culture supplied with 4 × 102 cells ml− 1 of N. oculata (FC 3). The second highest ephippia density was found in M. micrura cultures fed with 4 × 104 cells ml− 1 of N. oculata (FC 2) which produced a mean total of 93.3 ± 13.4 ephippia l− 1 in a population density of > 3000 individuals l− 1. However, with a population density of > 4000 individuals l− 1, but fed with the highest food concentration of 4 × 106 cells ml− 1 N. oculata (FC 1), no ephippia was produced although males were present in the culture. This study illustrates that ephippia were produced in high density cultures with the presence of males and insufficient food supply. Crowding could trigger the production of males, but was not an adequate stress factor for inducing the formation of ephippia. Similarly, food limitation alone did not induce the production of males and ephippia without crowding.

Starch is an edible polymer derived from plant basis. It is commonly used in food industry as it offers good stabilising effect. Moreover, starch can be easily modified either physically or chemically making it a very versatile source. For instance, its capability to be easily modified and coming from low cost source making starch as one of the most important ingredient in food preparation. There are currently varieties of commercially modified starch available in Malaysian market. For example, potato, corn, wheat and tapioca starch are presently on the top list. However, there are also numbers of unexplored native starch for example from fruits processing waste. Besides, these fruit by-products are considered as underutilised source of starch. Although there are few existing reported studies on starch extracted from fruits seed and other waste products, more new sources are believed to be explored in future according to particular starchbased products industries and demands. Therefore, this review discusses current starch based-products developments and application of unconventional starch in food industry. Acetylationacetic anhydride [153] Esterification -Dodecenyl succinic anhydride [154] Maize Acetylated (Ac) [156] Cross-linked [157] Acha (Digitaria exilis) Cross-linked with citric acid [158] Banana (green/unripe) Hydrochloric acid [159] Mango kernel (Mangifera indica L.) Hydrochloric acid [160] Rice (Oryza sativa L.) Citric acid, lactic acid and acetic acid [161] Acetylationacetic anhydride [162, 163] Cross linkingcitric acid [166] Sago Acid hydrolysis and hydroxypropylation [167] Acetylationacetic anhydride [168] Esterification -Octenyl succinic anhydride (OSA) [169] Durian (Durio zibethinus) seed starch Acetic acid [170] Cross-linking [171] Avocado (Persea americana, Miller) Acetic acid [172] Cross-linking [173] Black eyed pea (Vigna unguiculata) Acid hydrolysis -Concentrated hydrochloric acid (36% by weight) [174] Carioca beans (Phaseolus vulgaris L.; cv. Pérola)

Abstract. The aim of this study was to compare the specific growth rate and biomass productivity of microalgae in domestic wastewater according to the initial cell concentration. The initial microalgae cell concentrations tested started from 10 3 cell/mL, 10 4 cell/mL, 10 5 cell/mL, 10 6 cell/mL, and 10 7 cell/mL under outdoor condition. The result revealed that the highest biomass productivity occurred at 10 6 cell/mL concentration with a value of 1.24 × 10 4 cell/mL/day, 0.26 day -1 of specific growth rate, and a doubling time of 2.63 days. Meanwhile, the lowest biomass productivity occurred at 10 3 cell/mL concentration with the lowest specific growth rate of 0.1 day -1 and the longest doubling time, which reached up to 7.14 day. As a result, the initial cell concentration of microalgae did influence the algal biomass productivity and growth rate differently. Thus, the maximum growth rate and biomass productivity were obtained at 10 6 cell/mL concentration which is recommended to be used in biotechnology industries and any wastewater treatment.

Abstract. Greywater (GW) is identified as waste disposal from home activites that is discharging from laundry, bath and wash-basin. GW useful in irrigation of a garden and aids to reduce cost as well as maintain the environmental prosperity. This paper discussed the effectiveness of Botryococcus sp. to clean GW in phycoremediation treatment. This process involves as growing the Botryococcus sp. in the GW which is contributing to utilize supplements in GW for its grow. The results indicated that Botryococcus sp. is effective to reduce COD (88%), BOD (82%), TIC (76%), TC (58%), TN (52%), TOC (39%), Phosphate (37.5%) and pH (7%) for 100% concentration of GW. Meanwhile, for the 50% of GW concentration Botryococcus sp. capable to remove such as COD (83%), TIC (82%), BOD (68%), TN (67%), Phosphate (36.8%), TC (34%), TOC (31%) and pH (1.2%). Then, the study concludes that Botryococcus sp. can grow effectively in GW and be able to reduce the rate of nutrient in GW.

Discharge of household greywater into water bodies can lead to an increase in contamination levels in terms of the reduction in dissolved oxygen resources and rapid bacterial growth. Therefore, the quality of greywater has to be improved before the disposal process. The present review aimed to present a hybrid treatment system for the greywater generated from households. The hybrid system comprised a primary stage (a natural filtration unit) with a bioreactor system as the secondary treatment combined with microalgae for greywater treatment, as well as the natural flocculation process. The review discussed the efficiency of each stage in the removal of elements and nutrients. The hybrid system reviewed here represented an effective solution for the remediation of household greywater.

This study was undertaken to analyze the efficiency of Botryococcus sp. in the phycoremediation of domestic wastewater and to determine the variety of hydrocarbons derived from microalgal oil after phycoremediation. The study showed a significant (p < 0.05) reduction of pollutant loads of up to 93.9% chemical oxygen demand, 69.1% biochemical oxygen demand, 59.9% total nitrogen, 54.5% total organic carbon, and 36.8% phosphate. The average dry weight biomass produce was 0.1 g/L of wastewater. In addition, the dry weight biomass of Botryococcus sp. was found to contain 72.5% of crude oil. The composition analysis using Gas Chromatogram - Mass Spectrometry (GC-MS) found that phthalic acid, 2-ethylhexyltridecyl ester (CHO), contributed the highest percentage (71.6%) of the total hydrocarbon compounds to the extracted algae oil. The result of the study suggests that Botryococcus sp. can be used for effective phycoremediation, as well as to provide a sustainable hydrocarbon source as a value-added chemical for the bio-based plastic industry.

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